Research Coordination Network of Emerging Methodologies for Molecular Structure Determination in Biological Solids
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Emerging Methodologies for Molecular Structure Determination in Biological Solids
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Wednesday Jun. 28, 2017 Selected Publications by RCN-SCN Participants
MMA CUNY
  • Characterization of bovine patellar cartilage by NMR
  • Cytochrome P450 BM-3 in Complex with Its Substrate: Temperature-Dependent Spin
  • Biology of the Plant Cuticle
  • Molecular Interfacial Phenomena of Polymers and Biopolymers
  • J-based 2D homonuclear and heteronuclear correlation in solid-state proteins
  • Conformational Dynamics of Substrate in the Active Site of Cytochrome P450 BM-3/NPG Comple ...
  • Substrate product equilibrium on a reversible enzyme, triosephosphate isomerase
  • Assignment of congested NMR spectra: Carbonyl backbone enrichment via the Entner–Doudoroff ...
  • Solid-state NMR study and assignments of the KcsA potassium ion channel of S. lividans
  • Filamentous Phage Studied by Magic-Angle Spinning NMR: Resonance Assignment and Secondary ...
  • Using Trifluoroacetic Acid To Augment Studies of Potato Suberin Molecular Structure
  • 2H double quantum filtered (DQF) NMR spectroscopy of the nucleus pulposus tissues of the i ...
  • Backbone Assignments in Solid-State Proteins Using J-Based 3D Heteronuclear Correlation Sp ...
  • Solid state NMR: new tools for insight into enzyme function
  • Conformational Flexibility of a Microcrystalline Globular Protein: Order Parameters by Sol ...
  • Order parameters based on 13C1H, 13C1H2 and 13C1H3 heteronuclear dipolar powder patterns: ...
  • Resonance Assignments and Secondary Structure Analysis of E. coli Thioredoxin by Magic Ang ...
  • Nuclear spin noise imaging
  • Behavior of ordered sodium in enzymatically depleted cartilage tissue
  • Insight into framework destruction in ultramarine pigments.
  • Selective detection of ordered sodium signals via the central transition
  • Separated quadrupolar field experiment
  • Selecting ordered environments in NMR of spin 3/2 nuclei via frequency-sweep pulses
  • Frequency-selective quadrupolar MRI contrast
  • mprovement of resolution in solid state NMR spectra with J-decoupling: an analysis of line ...
  • Assignment of the Backbone Resonances for Microcrystalline Ubiquitin
  • Assignments of Carbon NMR Resonances for Microcrystalline Ubiquitin
  • Structural and dynamic studies of proteins by solid-state NMR spectroscopy: rapid movement ...
  • Characterization of Protein-Ligand Interactions by High-Resolution Solid-State NMR Spectro ...
  • Homo-nuclear 13C J-decoupling in uniformly 13C-enriched solid proteins.
  • Protein structure determination by high-resolution solid-state NMR spectroscopy: applicati ...
  • Structure determination of aligned systems by solid-state NMR magic angle spinning methods
  • Chlorine-35/37 NMR spectroscopy of solid amino acid hydrochlorides: refinement of hydrogen ...
  • Characterization of Folding Intermediates of a Domain-Swapped Protein by Solid-State NMR S ...
  • Three structural roles for water in bone observed by solid-state NMR.
  • 3-Methylglutaric acid as a (13)C solid-state NMR standard.
  • Characterization of Folding Intermediates of a Domain-Swapped Protein by Solid-State NMR S ...
  • 51V Solid-State Magic Angle Spinning NMR Spectroscopy of Vanadium Chloroperoxidase.
  • Locating hydrogen atoms in single crystal and uniaxially aligned amino acids by solid-stat ...
  • Magic-Angle Spinning NMR Studies of Cell Wall Bound Aromatic-Aliphatic Biopolyesters Assoc ...
  • A Solid-State NMR Study of the Dynamics and Interactions of Phenylalanine Rings in a Stath ...
  • Accurate Measurements of 13C-13C J-Couplings in the Rhodopsin Chromophore by Double-Quantu ...
  • High-Field NMR Studies of Molecular Recognition and Structure-Function Relationships in An ...
  • Capturing Intermediate Structures of Alzheimer's -Amyloid, A(1-40), by Solid-State NMR Spe ...
  • Structures of Staphylococcus aureus Cell-Wall Complexes with Vancomycin, Eremomycin, and C ...
  • Quantitative Analysis of Backbone Dynamics in a Crystalline Protein from Nitrogen-15 Spin- ...
  • Three Structural Roles for Water in Bone Observed by Solid-State NMR
  • Multiple-sample probe for solid-state NMR studies of pharmaceuticals
  • Zinc Solid-State NMR Spectroscopy of Human Carbonic Anhydrase: Implications for the Enzyma ...
  • Single-Crystal Studies of Peptide Prolyl and Glycyl 15N Shielding Tensors.
  • Membrane permeabilization, orientation, and antimicrobial mechanism of subtilosin A
  • In situ nuclear magnetic resonance investigations of lithium ions in carbon electrode mate ...
  • Molecular Structure of fd (f1, M13) Filamentous Bacteriophage Refined with Respect to X-ra ...
  • Structure and dynamics studies of BSP-24 to to investigate the role of bone sialoprotein I ...
  • NMR studies of modified nasicon-like, lithium conducting solid electrolytes*1
  • Magnetic resonance studies of chemically intercalated Li[sub x]V[sub 2]O[sub 5] aerogels.
  • Spectroscopic characterization of natural corals
  • Broadband Homonuclear Correlation Spectroscopy at High Magnetic Fields and MAS Frequencies
  • Multi-dimensional pulsed field gradient magic angle spinning NMR experiments on membranes
  • Using Switched Angle Spinning to Simplify NMR Spectra of Strongly Oriented Samples
  • Probing Specific Lipid-Protein Interaction by Saturation Transfer Difference NMR Spectrosc ...
  • Direct Characterization of the Folded, Unfolded and Urea-denatured States of the C-termina ...
  • Accurate Measurements of 13C-13C J-Couplings in the Rhodopsin Chromophore by Double-Quantu ...
  • Val659Glu Mutation within the Transmembrane Domain of ErbB-2: Effects Measured by 2H NMR i ...
  • Interaction of the Neuropeptide Met-Enkephalin with Zwitterionic and Negatively Charged Bi ...
  • Probing site-specific conformational distributions in protein folding with solid-state NMR
  • Backbone Conformational Constraints in a Microcrystalline U-15N-Labeled Protein by 3D Dipo ...
  • Motional Heterogeneity in Poly(ether-block-amide) Copolymers As Revealed by Solid-State NM ...
  • Binding of Peptides with Basic and Aromatic Residues to Bilayer Membranes
  • A 2D Solid-State NMR Experiment To Resolve Overlapping Aromatic Resonances of Thiophene-Ba ...
  • Tautomerism and 1H and 13C NMR assignment of methyl derivatives of 9-hydroxyphenalenone
  • Amplitude-modulated decoupling in rotating solids: A bimodal Floquet approach
  • Solid state 19F NMR methods for studying biomembranes
  • Characterization of Dynamics of Perdeuterated Proteins by MAS Solid-State NMR
  • Solid-State NMR Studies of the Structure, Dynamics, and Assembly of -Sheet Membrane Peptid ...
  • Ion Solvation by Channel Carbonyls Characterized by 17O Solid-State NMR at 21 T
  • Magic Angle Spinning Solid-State NMR Spectroscopy for Structural Studies of Protein Interf ...
  • Observation of Ligand Binding to Cytochrome P450 BM-3 by Means of Solid-State NMR Spectros ...
  • NMR studies of structure and dynamics in fruit cuticle polyesters.
  • Magnetic Resonance in Chemistry, special issue, Solid-state NMR on biological systems.
  • Unlocking the Molecular Structure of Fungal Melanin Using 13C Biosynthetic Labeling and So ...

  • Characterization of bovine patellar cartilage by NMR
    Metabolic and structural changes in cartilage tissue are thought to be at the root of degenerative joint disease. We identify here the NMR resonances in bovine patellar cartilage tissue by static and high-resolution magic angle spinning (HRMAS) NMR spectroscopy, 1H-13C heteronuclear single-quantum correlation (HSQC) spectroscopy, total correlation spectroscopy (TOCSY), and saturation transfer experiments. Some differences between the patellar cartilage samples studied here and earlier nasal cartilage and intervertebrate disc studies were found. In addition, we show assignments downfield of the water signal, which also includes the assignment of amide and hydroxy protons on the basis of their exchange ability with water. These results will allow an identification of spectroscopic markers of cartilage degradation using techniques such as chemical exchange saturation transfer imaging.Wen Ling 1, Ravinder R. Regatte 2, Mark E. Schweitzer 2, Alexej Jerschow 1 *1Chemistry Department, New York University, New York, NY 10003, USA2Center for Biomedical Imaging, Radiology Department, New York University School of Medicine, New York, NY 10003, USAhttp://www3.interscience.wiley.com/cgi-bin/fulltext/114294661/PDFSTART
    Cytochrome P450 BM-3 in Complex with Its Substrate: Temperature-Dependent Spin
    In structural studies of cytochrome P450 enzymes, substrates have been seen to bind in a variety of modes; it is important toidentify those with the closest resemblance to the configurations adopted during selective oxidation. We attempt here to identify conditions in which the catalytic binding mode of cytochrome P450 BM-3 saturated with N-palmitoylglycine is highly populated. When the substrate binds directly atop the heme, primed for oxidation, displacement of the water ligand is necessary, and thereby the ferric heme is generally converted from low-spin to high-spin. Using both optical spectroscopy and solid-state nuclear magnetic resonance, studying both the full length enzyme and the isolated heme domain, we show that a high population of the high-spin form is seen at room temperature and above,but not at reduced temperatures. In contrast, the reduced state exhibits high spin throughout the temperature range. The isotropic chemical shift of deuterons in the substrate bound to the oxidized and reduced forms of the enzyme was temperature-dependent, consistent with the presence of a nearby paramagnetic center, but temperature-independent for the diamagnetic CO-bound form, and for the free form of the compound. The reduced (ferrous heme) species shows Curie law dependence of the 2H substrate chemical shift with respect to temperature from to +35 °C, but the oxidized (ferric heme) species showed a pronounced non-Curie dependence in both the 2H and the 13C shift of the substrate’s methyl group, with the effect of the paramagnetic heme at low temperatures being much reduced. These data are consistent with a mixture of at least two binding modes in rapid equilibrium wherein the heme is high-spin at room temperature but low-spin at cryogenic temperatures.T. Jovanovic, M. Harris, and A. E. McDermott.Columbia University, Department of Chemistry, MC 3113, 3000 Broadway, New York, New York 10027, USA.http://www.springer.co.at/periodicals/article_pdf/xxxxxxxxx696xxxxxx417109_1.pdf
    Biology of the Plant Cuticle
    Annual Plant Reviews, Volume 23A much clearer picture is now emerging of the fine structure of the plant cuticle and its surface, the composition of cuticular waxes and the biosynthetic pathways leading to them. Studies assessing the impact of UV radiation on plant life have emphasized the role of the cuticle and underlying epidermis as optical filters for solar radiation. The field concerned with the diffusive transport of lipophilic organic non-electrolytes across the plant cuticle has reached a state of maturity. A new paradigm has recently been proposed for the diffusion of polar compounds and water across the cuticle. In the context of plant ecophysiology, cuticular transpiration can now be placed in the perspective of whole-leaf water relations. New and unexpected roles have been assigned to the cuticle in plant development and pollen-stigma interactions. Finally, much progress has been made in understanding the cuticle as a specific and extraordinary substrate for the interactions of the plant with microorganisms, fungi and insects.This volume details the major developments of recent years in this important interdisciplinary area. It is directed at researchers and professionals in plant biochemistry, plant physiology, plant ecology, phytopathology and environmental microbiology, in both the academic and industrial sectors.Edited by: Markus Riederer (Julius-von-Sachs-Institut für Biowissenschaften, Universität Würzburg, Würzburg) and Caroline Muller (Julius-von-Sachs-Institut für Biowissenschaften, Universität Würzburg, Würzburg).Invited chapter 'The Cutin Biopolymer Matrix'. Ruth E. Stark, Shiying Tian.http://www.blackwellpublishing.com/book.asp?ref=9781405132688
    Molecular Interfacial Phenomena of Polymers and Biopolymers
    - reviews key research in this hot area including biomaterials - examines polymeric interfacial properties and reviews medical and other practical applications - edited by a leading authority with contributions from distinguished experts worldwideOne of the most exciting areas of polymer research is the study of interfacial phenomena and their practical applications. This major work reviews the key research in this important area and is used in such areas as biomaterials.Part One looks at the thermodynamics, kinetics and other fundamental properties of polymer surfaces and interfaces. The second part of the book reviews ways of characterising and manipulating interfacial phenomena. It includes examples of practical applications such as vaccine delivery, tissue engineering and the development of therapeutic lung surfactants.With its distinguished editor and international team of contributors, Molecular interfacial phenomena of polymers and biopolymers is a standard work on understanding polymeric interfacial properties and their medical and other practical applications.Edited by P Chen, University of Waterloo, CanadaJ.D. Batteas and Ruth E. Stark, invited Chapter 'Surface and Interfacial Studies of Plant Biopolymers'http://www.woodheadpublishing.com/en/book.aspx?bookID=800
    J-based 2D homonuclear and heteronuclear correlation in solid-state proteins
    Scalar-based two-dimensional heteronuclear experiments are reported for NCO and NCA chemical shift correlation in the solid state. In conjunction with homonuclear CACO correlation, these experiments form a useful set for tracing connectivities and assigning backbone resonances in solid-state proteins. The applicability of this approach is demonstrated on two proteins, the 1 immunoglobulin binding domain of protein G at 9.4 T and reassembled thioredoxin at 14.1 T, using different decoupling conditions and MAS frequencies. These constant-time J-based correlation experiments exhibit increased resolution in the indirect dimension owing to homonuclear and heteronuclear decoupling, and because the indirect evolution and transfer periods are combined into a single constant time interval, this increased resolution is not obtained at the cost of sensitivity. These experiments are also shown to be compatible with in-phase anti-phase (IPAP) selection, giving increased resolution in the directly detected dimension.Lingling Chen 1, J. Michael Kaiser 1, Jinfeng Lai 1, Tatyana Polenova 2, Jun Yang 2, Chad M. Rienstra 3, Leonard J. Mueller 1Department of Chemistry, University of California, Riverside, California 92521, USA2Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, USA3Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USAhttp://www3.interscience.wiley.com/cgi-bin/fulltext/117871372/PDFSTART
    Conformational Dynamics of Substrate in the Active Site of Cytochrome P450 BM-3/NPG Complex: Insights from NMR Order Parameters
    Ligand NMR order parameters are calculated from replica exchange molecular dynamics simulations of the cytochrome P450 BM-3/NPG complex. These are found to be in agreement with experimental NMR order parameters at room temperature consistent with an equilibrium between unproductive and productive conformations of this complex, with the latter state being predominant at physiological temperatures. The calculations show that the low experimental order parameters at room temperature reflect angular motion of the productive state rather than transitions from one state to the other. The wider distribution of bond orientations and concomitant lower-order parameters of the terminal bond of the ligand corresponding to the productive state is consistent with the proposal for an entropic mechanism for the stabilization of the productive conformational state. This study further supports the recently proposed thermal activation mechanism for this enzymatic system.Krishna Pratap Ravindranathan, Emilio Gallicchio, Ann E. McDermott, and Ronald M. Levyhttp://pubs.acs.org/cgi-bin/abstract.cgi/jacsat/2007/129/i03/abs/ja0672371.html
    Substrate product equilibrium on a reversible enzyme, triosephosphate isomerase
    The highly efficient glycolytic enzyme, triosephosphate isomerase, is expected to differentially stabilize the proposed stable reaction species: ketone, aldehyde, and enediol(ate). The identity and steady-state populations of the chemical entities bound to triosephosphate isomerase have been probed by using solid- and solution-state NMR. The 13C-enriched ketone substrate, dihydroxyacetone phosphate, was bound to the enzyme and characterized at steady state over a range of sample conditions. The ketone substrate was observed to be the major species over a temperature range from –60°C to 15°C. Thus, there is no suggestion that the enzyme preferentially stabilizes the reactive intermediate or the product. The predominance of dihydroxyacetone phosphate on the enzyme would support a mechanism in which the initial proton abstraction in the reaction from dihydroxyacetone phosphate to D-glyceraldehyde 3-phosphate is significantly slower than the subsequent chemical steps.Sharon Rozovsky, and Ann E. McDermotthttp://www.pnas.org/cgi/reprint/104/7/2080?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=1&andorexacttitle=and&andorexacttitleabs=and&andorexactfulltext=and&searchid=1&FIRSTINDEX=0&sortspec=relevance&firstpage=2080&resourcetype=HWCIT
    Assignment of congested NMR spectra: Carbonyl backbone enrichment via the Entner–Doudoroff pathway
    In NMR spectra of complex proteins, sparse isotope enrichment can be important, in that the removal of many 13C–13C homonuclear J-couplings can narrow the lines and thereby facilitate the process of spectral assignment and structure elucidation. We present a simple scheme for selective yet extensive isotopic enrichment applicable for production of proteins in organisms utilizing the Entner–Doudoroff (ED) metabolic pathway. An enrichment scheme so derived is demonstrated in the context of a magic-angle spinning solid-state NMR (MAS SSNMR) study of Pf1 bacteriophage, the host of which is Pseudomonas aeruginosa, strain K (PAK), an organism that uses the ED pathway for glucose catabolism. The intact and infectious Pf1 phage in this study was produced by infected PAK cells grown on a minimal medium containing 1-13C d-glucose (13C in position 1) as the sole carbon source, as well as 15NH4Cl as the only nitrogen source. The 37 MDa Pf1 phage consists of about 93% major coat protein, 1% minor coat proteins, and 6% single-stranded, circular DNA. As a consequence of this composition and the enrichment scheme, the resonances in the MAS SSNMR spectra of the Pf1 sample were almost exclusively due to carbonyl carbons in the major coat protein. Moreover, 3D heteronuclear NCOCX correlation experiments also show that the amino acids leucine, serine, glycine, and tyrosine were not isotopically enriched in their carbonyl positions (although most other amino acids were), which is as expected based upon considerations of the ED metabolic pathway. 3D NCOCX NMR data and 2D 15N–15N data provided strong verification of many previous assignments of 15N amide and 13C carbonyl shifts in this highly congested spectrum; both the semi-selective enrichment patterns and the narrowed linewidths allowed for greater certainty in the assignments as compared with use of uniformly enriched samples alone.Amir Goldbourt, Loren A. Day and Ann E. McDermotthttp://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6WJX-4PFDDV9-1-S&_cdi=6890&_user=699445&_orig=search&_coverDate=12%2F31%2F2007&_sk=998109997&view=c&wchp=dGLbVtb-zSkzS&md5=ca62a7404378489cef94de3e143faa93&ie=/sdarticle.pdf
    Solid-state NMR study and assignments of the KcsA potassium ion channel of S. lividans
    The extraordinary efficiency and selectivity of potassium channels have made them ideal systems for biophysical and functional studies of ion conduction. We carried out solid-state NMR studies of the selectivity filter region of the protein. Partial site-specific assignments of the NMR signals were obtained based on high field multidimensional solid-state NMR spectra of uniformly 13C, 15N enriched KcsA potassium channel from Streptomyces lividans. Both backbone and sidechain atoms were assigned for residues V76-D80 and P83-L90, in and near the selectivity filter region of the protein; this region exhibits good dispersion and useful chemical shift fingerprints. This study will enable structure, dynamic and mechanistic studies of ion conduction by NMR.Krisztina Varga, Lin Tian and Ann E. McDermotthttp://www.sciencedirect.com/science?_ob=MImg&_imagekey=B73DJ-4PNFV8M-1-1&_cdi=11472&_user=699445&_orig=search&_coverDate=12%2F31%2F2007&_sk=982259987&view=c&wchp=dGLzVzz-zSkWA&md5=504a0b45cc988e562cc7f3776adbe5de&ie=/sdarticle.pdf
    Filamentous Phage Studied by Magic-Angle Spinning NMR: Resonance Assignment and Secondary Structure of the Coat Protein in Pf1
    Assignments are presented for resonances in the magic-angle spinning solid-state NMR spectra of the major coat protein subunit of the filamentous bacteriophage Pf1. NMR spectra were collected on uniformly 13C and 15N isotopically enriched, polyethylene glycol precipitated samples of fully infectious and hydrated phage. Site-specific assignments were achieved for 231 of the 251 labeled atoms (92%) of the 46-residue-long coat protein, including 136 of the 138 backbone atoms, by means of two- and three-dimensional 15N and 13C correlation experiments. A single chemical shift was observed for the vast majority of atoms, suggesting a single conformation for the 7300 subunits in the 36 MDa virion in its high-temperature form. On the other hand, multiple chemical shifts were observed for the C, C, and C atoms of T5 in the helix terminus and the C and C atoms of M42 in the DNA interaction domain. The chemical shifts of the backbone atoms indicate that the coat protein conformation involves a 40-residue continuous -helix extending from residue 6 to the C-terminus. Amir Goldbourt, Benjamin J. Gross, Loren A. Day, and Ann E. McDermott* http://pubs.acs.org/cgi-bin/abstract.cgi/jacsat/2007/129/i08/abs/ja066928u.html
    Using Trifluoroacetic Acid To Augment Studies of Potato Suberin Molecular Structure
    Systematically varied reaction times and concentrations of trifluoroacetic acid (TFA) have been used to remove polysaccharides associated with suberin isolated from potato wound periderm, thereby augmenting spectroscopic determinations of the molecular structure of this protective plant polyester. Treatments with dilute TFA left a residual insoluble material for which both solid-state 13C and 1H NMR spectra displayed significant improvements in resolution without compromising the integrity of the protective plant polyester, whereas higher concentrations of TFA made it possible to achieve controlled hydrolysis of the suberin aliphatic or aromatic domains. Among the isolated fragments were two hydroxyphenyl derivatives reported previously in lignins and a novel aliphatic-aromatic ester trimer that is identified provisionally. Together these protocols help to characterize the carbohydrate types that are bound covalently to the suberin polyester and to identify the interunit covalent linkages among the aliphatic ester, phenolic, and carbohydrate moieties in suberized potato tissue. The strategies described herein may also advance molecular-level investigations of lignocellulosic materials or vegetable tissues that exhibit strengthened intercellular adhesion. Daniel Arrieta-Baez and Ruth E. Starkhttp://pubs.acs.org/cgi-bin/abstract.cgi/jafcau/2006/54/i26/abs/jf0611522.html
    2H double quantum filtered (DQF) NMR spectroscopy of the nucleus pulposus tissues of the intervertebral disc
    Deuterium (2H) double-quantum filtered (DQF) NMR spectroscopy of nucleus pulposus (NP) tissues from human intervertebral discs is reported. The DQF spectral intensities, DQ build-up rates, and DQF-detected rotating-frame spin-lattice relaxation times are sensitive to the degree of hydration of the NP tissue, and display a monotonous correlation with age between 15 and 80 years. The implications of this work are that the changes in water dynamics as detected via DQF NMR spectroscopy may be used as a probe of tissue degeneration in NP, particularly in the early stages of degeneration to which most standard NMR methods are not sensitive. William Perea 1, Marco Cannella 2, Jun Yang 1, Alexander J. Vega 1, Tatyana Polenova 1 *, Michele Marcolongohttp://www3.interscience.wiley.com/cgi-bin/fulltext/114274358/PDFSTART
    Backbone Assignments in Solid-State Proteins Using J-Based 3D Heteronuclear Correlation Spectroscopy
    3D NCACO, NCOCA, and CANCO scalar-coupling driven correlation experiments are presented for protein backbone assignments in the solid-state. These J-MAS experiments show superior resolution in the indirect dimensions through the elimination of heteronuclear and homonuclear couplings and enhanced sensitivity, which allow us to trace out the entire protein backbone for GB1. Our results demonstrate that scalar-based methods are sufficiently well-developed to serve as a complementary tool to dipolar methods, which will be especially useful for assignment of large proteins, where resonance overlap presents a major challenge to solid-state NMR. Lingling Chen, J. Michael Kaiser, Tatyana Polenova,# Jun Yang,# Chad M. Rienstra, and Leonard J. Mueller* http://pubs.acs.org/cgi-bin/abstract.cgi/jacsat/2007/129/i35/abs/ja073498e.html
    Solid state NMR: new tools for insight into enzyme function
    NMR has had considerable impact in enzymology, probing evidence for ionization states, conformational ‘strain’, compressed interactions, electronically unusual species, and conformational dynamics of enzymes. Solid-state NMR is becoming increasingly important in studying enzymes because of a number of recent tools for analysis of proteins by SSNMR, and because of the growing ability to isolate the species of interest for analysis. Here, we review recent studies of a Michaelis complex, of the dynamic functioning of membrane-associated enzymes, and initial studies of several enzymes with redox-active and paramagnetic centers. Ann McDermott, Tatyana Polenova. http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6VS6-4R05J2F-4-9&_cdi=6254&_user=699445&_orig=search&_coverDate=10%2F31%2F2007&_sk=999829994&view=c&wchp=dGLbVtz-zSkzk&md5=277b9e6854c0f5ea57a2c61227631afa&ie=/sdarticle.pdf
    Conformational Flexibility of a Microcrystalline Globular Protein: Order Parameters by Solid-State NMR Spectroscopy
    he majority of protein structures are determined in the crystalline state, yet few methods exist for the characterization of dynamics for crystalline biomolecules. Solid-state NMR can be used to probe detailed dynamic information in crystalline biomolecules. Recent advances in high-resolution solid-state NMR have enabled the site-specific assignment of 13C and 15N nuclei in proteins. With the use of multidimensional separated-local-field experiments, we report the backbone and side chain conformational dynamics of ubiquitin, a globular microcrystalline protein. The measurements of molecular conformational order parameters are based on heteronuclear dipolar couplings, and they are correlated to assigned chemical shifts, to obtain a global perspective on the sub-microsecond dynamics in microcrystalline ubiquitin. A total of 38 C, 35 C and multiple side chain unique order parameters are collected, and they reveal the high mobility of ubiquitin in the microcrystalline state. In general the side chains show elevated motion in comparison with the backbone sites. The data are compared to solution NMR order parameter measurements on ubiquitin. The SSNMR measurements are sensitive to motions on a broader time scale (low microsecond and faster) than solution NMR measurements (low nanosecond and faster), and the SSNMR order parameters are generally lower than the corresponding solution values. Unlike solution NMR relaxation-based order parameters, order parameters for 13C1H2 spin systems are readily measured from the powder line shape data. These results illustrate the potential for detailed, extensive, and site-specific dynamic studies of biopolymers by solid-state NMR. Justin L. Lorieau and Ann E. McDermotthttp://pubs.acs.org/cgi-bin/abstract.cgi/jacsat/2006/128/i35/abs/ja062443u.html
    Order parameters based on 13C1H, 13C1H2 and 13C1H3 heteronuclear dipolar powder patterns: a comparison of MAS-based solid-state NMR sequences
    Order parameters describing conformational exchange processes on the nanosecond to microsecond timescale can be obtained from powder patterns in solid-state NMR (SSNMR) experiments.[1-3] Extensions of these experiments to magic-angle spinning (MAS) based high-resolution experiments have been demonstrated,[4-6] which show a great promise for site-specific probes of biopolymers. In this study, we present a detailed comparison of two pulse sequences, transverse Manfield-Rhim-Elleman-Vaughn (T-MREV) and Lee-Goldburg cross-polarization (LGCP), using experimental and simulation tools to explore their utility in the study of order parameters. We discuss systematic errors due to passively coupled 13C or 1H nuclei, as well as due to B1 inhomogeneity. Both pulse sequences can provide quantitative measurements of the order parameter, but the LGCP experiment is capable of greater accuracy provided that the B1 field is highly homogeneous. The T-MREV experiment is far better compensated for B1 inhomogeneity, and it also performs better in situations with limited signal. Justin Lorieau, Ann E. McDermott http://www3.interscience.wiley.com/cgi-bin/fulltext/112410577/PDFSTART
    Resonance Assignments and Secondary Structure Analysis of E. coli Thioredoxin by Magic Angle Spinning Solid-State NMR Spectroscopy
    De novo site-specific 13C and 15N backbone and sidechain resonance assignments are presented for uniformly enriched E. coli thioredoxin, established using two-dimensional homo- and heteronuclear solid-state magic angle spinning NMR correlation spectroscopy. Backbone dihedral angles and secondary structure were derived from the statistical analysis of the secondary chemical shifts, and are in good agreement with solution values for the intact full-length thioredoxin, with the exception of a small number of residues located at the termini of the individual secondary structure elements. A large number of cross-peaks observed in the DARR spectra with long mixing times correspond to the pairs of carbon atoms separated by 4-6 Å, suggesting that DARR could be efficiently employed for observation of medium- and long-range correlations. The 108 amino acid residue E. coli thioredoxin is the largest uniformly enriched protein assigned to this degree of completeness by solid-state NMR spectroscopy to date. It is anticipated that with a combination of two-dimensional correlation experiments and high magnetic fields, resonance assignments and secondary structure can be generally derived for other noncrystalline proteins. Dabeiba Marulanda, Maria Luisa Tasayco,* Marcela Cataldi, Vilma Arriaran, and Tatyana Polenova* http://pubs.acs.org/cgi-bin/abstract.cgi/jpcbfk/2005/109/i38/abs/jp052774d.html
    Nuclear spin noise imaging
    NMR images were obtained from the proton spin noise signals of a water-containing phantom, which was placed in the highly tuned, low-noise resonant circuit of a cryogenically cooled NMR probe in the presence of systematically varied magnetic field gradients. The spatially resolved proton spin density was obtained from the raw signal by a modified projection–reconstruction protocol. Although spin noise imaging is inherently less sensitive than conventional magnetic resonance imaging, it affords an entirely noninvasive visualization of the interior of opaque objects or subjects. Thus, tomography becomes possible even when neither x-ray nor radio frequency radiation can be applied for technical or safety reasons. Norbert Müller{dagger}, and Alexej Jerschow. http://www.pnas.org/cgi/reprint/103/18/6790?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&fulltext=jerschow&searchid=1&FIRSTINDEX=0&resourcetype=HWCIT
    Behavior of ordered sodium in enzymatically depleted cartilage tissue
    The onset of cartilage tissue disorders can be characterized by a loss of proteoglycans (PGs) and diagnosed by contrast-enhanced proton (1H) MRI techniques, as well as sodium MRI. The behavior of sodium located in anisotropic environments, is examined as a function of cartilage degeneration. PGs are proteolytically depleted from the cartilage samples, which gives rise to a decrease of the ordered sodium content. More surprisingly, however, the residual quadrupolar couplings are shown to increase with increasing depletion levels. Since the residual quadrupolar couplings are intimately related to local order and anisotropic motion, measuring their distribution in cartilage may provide insight into the structural changes that occur within the tissue upon degradation. In this study relatively mild orientational dependence of the couplings was found. Little or no free sodium was observed in the cartilage specimens under study. Wen Ling , Ravinder R. Regatte , Mark E. Schweitzer , Alexej Jerschow http://www3.interscience.wiley.com/cgi-bin/fulltext/113389710/PDFSTART
    Insight into framework destruction in ultramarine pigments.
    We report key evidence on the framework destruction in ultramarine pigments upon color fading. Experiments on faded pigments in a fresco painting environment reveal that the paramagnetic chromophores are set free via sodalite framework destruction and are subsequently degraded. Fading in acidic media produces similar results, although a larger number of beta-cages appear to be destroyed, and H2S is released. The findings are further supported by studies on natural and synthetic ultramarine pigments of various shades via solid-state resonance-Raman spectroscopy, colorimentry, and solid-state 29Si and 27Al NMR spectroscopy. NMR parameters are shown to correlate well with the intensities of Raman signals corresponding to the S3(-*) chromophores. A further correlation is established between the colorimetric parameters, L* (lightness) and C* (chroma), and the paramagnetic shift and paramagnetic linebroadening in NMR spectra for both 27Al and 29Si.Del Federico E, Shöfberger W, Schelvis J, Kapetanaki S, Tyne L, Jerschow A.http://pubs.acs.org/cgi-bin/searchRedirect.cgi/inocaj/2006/45/i03/pdf/ic050903z.pdf
    Selective detection of ordered sodium signals via the central transition
    Given the correlation between the concentrations of ordered 23Na and the onset of tissue disorders, the ability to select the signal from ordered 23Na over that of free 23Na is of particular importance and can greatly enhance the potential of 23Na-MRI as a diagnostic tool. Here, we describe a simple method that selectively detects the central transition of ordered sodium while minimizing the signal from free sodium. Our method relies upon the influence of the quadrupolar interaction on nutation frequencies and may also benefit solid-state imaging experiments. Both a liquid crystalline environment and a cartilage sample are used to demonstrate a clean separation between anisotropic and isotropic regions in the experiments. Jennifer Choy, Wen Ling and Alexej Jerschow, http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6WJX-4J8KNPN-1-1K&_cdi=6890&_user=699445&_orig=search&_coverDate=05%2F31%2F2006&_sk=998199998&view=c&wchp=dGLbVzW-zSkzV&md5=c08c3dd68dbb221844ec29c3b5da669e&ie=/sdarticle.pdf
    Separated quadrupolar field experiment
    We describe an NMR experiment that produces spectra correlating the first-order quadrupolar spectrum and the central transition spectrum of half-integer quadrupolar spins, allowing one to separate the quadrupolar parameters in overlapping spectra under both static and magic-angle-spinning conditions. Promising fields of applications include situations where the sample cannot easily be rotated, or where it cannot be rotated at the magic angle.Rajeev Kumar, Wen Ling, Wolfgang Schoefberger and Alexej Jerschow. http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6WJX-4DTKM4T-5-1&_cdi=6890&_user=699445&_orig=search&_coverDate=02%2F01%2F2005&_sk=998279997&view=c&wchp=dGLbVzW-zSkWW&md5=d772c7b19721e6fa5bdb28730cd3fb9d&ie=/sdarticle.pdf
    Selecting ordered environments in NMR of spin 3/2 nuclei via frequency-sweep pulses
    We demonstrate that frequency-swept pulses can be used for the selective and enhanced detection of quadrupolar nuclei located in anisotropic environments. The primary driving force for this technique development is the field of sodium-MRI, where sodium signals from locally ordered environments are known to be diagnostic of cartilage defects. We demonstrate here simple one-dimensional images of model systems, in which the signals from free sodium ions are suppressed, while ordered sodium is detected via the narrow central transition signal. Wen Ling and Alexej. Jerschow. http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6WJX-4GNCJ3C-2-M&_cdi=6890&_user=699445&_orig=search&_coverDate=10%2F31%2F2005&_sk=998239997&view=c&wchp=dGLbVzW-zSkWb&md5=112935ac3808b0616b0a3e0f7723fb68&ie=/sdarticle.pdf
    Frequency-selective quadrupolar MRI contrast
    A method for the selective detection of quadrupolar nuclei located in anisotropic environments is presented. The image contrast can be tuned to the degree of anisotropy in the sample by using frequency-swept pulsed. These methods are particularly useful in the field of sodium-MRI, where sodium signals from locally-ordered environments provide diagnostic information. In solid-state MRI, these methods could be useful for probing structural defects within the sample. We demonstrate here one-dimensional images, in which the pixel contrast indicates the presence or absence of quadrupolar coupling within a certain frequency range. Wen Ling and Alexej Jerschow. http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6THK-4HF5KDB-1-2K&_cdi=5285&_user=699445&_orig=search&_coverDate=02%2F28%2F2006&_sk=999709998&view=c&wchp=dGLbVlz-zSkWW&md5=996682f24b9dbe268dc9ae2ea63c1f0c&ie=/sdarticle.pdf
    mprovement of resolution in solid state NMR spectra with J-decoupling: an analysis of lineshape contributions in uniformly 13C-enriched amino acids and proteins
    In magic angle spinning (MAS) NMR spectra of highly and uniformly 13C,15N-enriched amino acids and proteins, homo-nuclear coupling interactions contribute significantly to the 13C linewidths, particularly for moderate applied magnetic field strengths and sample spinning frequencies. In this work, we attempted to dissect, analyze, and control the contributions of J-coupling and residual homo-nuclear dipolar coupling interactions to the linewidths of uniformly 13C,15N-enriched crystalline alanine; these studies were carried out at 9.4 T using a range of spinning frequencies from 5 to 15 kHz. The anisotropic second-order dipolar shifts and the J-splittings are comparable in their contribution to the linewidths, but behave very differently in terms of experimental protocols for line narrowing. In contrast to the J-coupling interactions, the second-order dipolar broadening cannot be refocused using selective pulses on the passively coupled spin. We carried out experiments to remove or refocus the 13C J-coupling interactions (ω1 J-decoupling) using a selective DANTE pulse in the center of the indirect evolution period. Inversion profiles and bandwidths of selective DANTE pulses acting on transverse magnetization, in the regime of moderate spinning frequencies, were characterized computationally and experimentally. A dramatic improvement in the resolution of the 2D spectrum was achieved when this decoupling protocol was employed. Tatyana I. Igumenova, Ann E. McDermott.http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6WJX-49CSY97-1-5F&_cdi=6890&_user=699445&_orig=search&_coverDate=10%2F31%2F2003&_sk=998359997&view=c&wchp=dGLbVzz-zSkWW&md5=9d516b0549139d932298efbb3a0ad2f0&ie=/sdarticle.pdf
    Assignment of the Backbone Resonances for Microcrystalline Ubiquitin
    Site-specific assignments for the solid-state NMR spectra of uniformly 13C,15N-enriched ubiquitin are described. The assignments are derived from three three-dimensional 15N-13C-13C correlation spectra collected at 400 MHz on microcrystalline material. A few residues (the loop near Threonine 9 and the C-terminal fragment) were missing and correspond to regions previously reported to be mobile on the basis of X-ray crystallography and solution NMR studies. A few additional sites exhibit shifts that differ from previously reported solution NMR assignments. Nonetheless, these de novo assignments indicate close agreement between the chemical shifts observed in solution and those in microcrystalline or precipitated solids. The methods utilized are likely to be generally applicable for other noncrystalline, nonsoluble proteins.Tatyana I. Igumenova,# A. Joshua Wand, and Ann E. McDermott* http://pubs.acs.org/cgi-bin/abstract.cgi/jacsat/2004/126/i16/abs/ja030546w.html
    Assignments of Carbon NMR Resonances for Microcrystalline Ubiquitin
    Solid-state NMR 2D spectroscopy was used to correlate carbon backbone and side-chain chemical shifts for uniformly 13C,15N-enriched microcrystalline ubiquitin. High applied field strengths, 800 MHz for protons, moderate proton decoupling fields, 80-100 kHz, and high magic angle sample spinning frequencies, 20 kHz, were used to narrow the most of the carbon line widths to 0.5-0.8 ppm. Homonuclear magnetization transfer was effected by matching the proton RF field to the spinning frequency, the so-called dipolar-assisted rotational resonance (DARR) (Takegoshi, K.; Nakamura, S.; Terao, T. Chem. Phys. Lett. 2001, 344, 631-637), and a mixing time of 20 ms was used to maximize the intensity of one-bond transfers between carbon atoms. This polarization transfer sequence resulted in roughly 14% transfer efficiencies for directly bonded carbon pairs and 4% transfer efficiencies for carbons separated by a third carbon. With this simple procedure, the majority of the one-bond correlations was observed with moderate transfer efficiencies, and many two-bond correlations were also observed with weaker intensities. Spin systems could be identified for more than half of the amino acid side chains, and site-specific assignments were readily possible via comparison with 400 MHz 15N-13C-13C correlation spectroscopy (described separately).Tatyana I. Igumenova,# Ann E. McDermott,* Kurt W. Zilm,* Rachel W. Martin, Eric K. Paulson, and A. Joshua Wand http://pubs.acs.org/cgi-bin/abstract.cgi/jacsat/2004/126/i21/abs/ja030547o.html
    Structural and dynamic studies of proteins by solid-state NMR spectroscopy: rapid movement forward.
    Starting only a few years ago, many solid-state NMR spectroscopy laboratories have become engaged in solving the complete structures of biological macromolecules using high-resolution methods based on magic angle spinning. These efforts typically involve structurally homogeneous samples, and utilize recently developed pulse sequences for the sequential correlation of resonances, the detection of tertiary contacts and the characterization of torsion angles. Thereby, systems have been studied that evaded other, more established, structure determination methods.McDermott AE.Columbia University, Department of Chemistry, MC 3113, 3000 Broadway, New York, New York 10027, USA. http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6VS6-4DBKK13-1-C&_cdi=6254&_user=699445&_orig=search&_coverDate=10%2F01%2F2004&_sk=999859994&view=c&wchp=dGLbVtz-zSkWW&md5=1a4d8fc62fc5a61f978ce0ec6b1d2e0c&ie=/sdarticle.pdf
    Characterization of Protein-Ligand Interactions by High-Resolution Solid-State NMR Spectroscopy
    A novel approach for detection of ligand binding to a protein in solid samples is described. Hydrated precipitates of the anti-apoptotic protein Bcl-xL show well-resolved 13C-13C 2D solid-state NMR spectra that allow site-specific assignment of resonances for many residues in uniformly 13C-enriched samples. Binding of a small peptide or drug-like organic molecule leads to changes in the chemical shift of resonances from multiple residues in the protein that can be monitored to characterize binding. Differential chemical shifts can be used to distinguish between direct protein-ligand contacts and small conformational changes of the protein induced by ligand binding. The agreement with prior solution-state NMR results indicates that the binding pocket in solid and liquid samples is similar for this protein. Advantages of different labeling schemes involving selective 13C enrichment of methyl groups of Ala, Val, Leu, and Ile (C1) for characterizing protein-ligand interactions are also discussed. It is demonstrated that high-resolution solid-state NMR spectroscopy on uniformly or extensively 13C-enriched samples has the potential to screen proteins of moderate size (~20 kDa) for ligand binding as hydrated solids. The results presented here suggest the possibility of using solid-state NMR to study ligand binding in proteins not amenable to solution NMR. Stephan G. Zech, Edward Olejniczak, Philip Hajduk, Jamey Mack, and Ann E. McDermott*Contribution from the Department of Chemistry, Columbia University, New York, New York 10027, and Pharmaceutical Discovery Devision, Abbott Laboratories, Abbott Park, Illinois 60064 http://pubs.acs.org/cgi-bin/searchRedirect.cgi/jacsat/2004/126/i43/pdf/ja040086m.pdf
    Homo-nuclear 13C J-decoupling in uniformly 13C-enriched solid proteins.
    Recently, we reported an analysis of carbon lineshapes in high resolution solid-state NMR spectra of uniformly 13C-enriched amino acids. Application of a 13C J-decoupling protocol during the carbon chemical shift evolution period allowed us to separate the contribution of the second-order dipolar shift from that of the 13C-13C J-coupling interactions to carbon linewidths. In this work, we have extended this approach to microcrystalline proteins. We describe the performance of the J-decoupling sequence applied to remove homo-nuclear 13C J-couplings in the 13C spectra of ubiquitin. Analysis of the J-decoupling efficiency for C(alpha) and carbonyl protein sites showed that a significant gain in resolution can be achieved. Igumenova TI, McDermott AE.Department of Chemistry, Columbia University, 3000 Broadway MC 3113, New York, NY 10027, USA.http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6WJX-4FW7R1G-2-1&_cdi=6890&_user=699445&_orig=search&_coverDate=07%2F31%2F2005&_sk=998249998&view=c&wchp=dGLbVzz-zSkWA&md5=25cb77a933176819c6de4264790ab7cc&ie=/sdarticle.pdf
    Protein structure determination by high-resolution solid-state NMR spectroscopy: application to microcrystalline ubiquitin.
    High-resolution solid-state NMR spectroscopy has become a promising method for the determination of three-dimensional protein structures for systems which are difficult to crystallize or exhibit low solubility. Here we describe the structure determination of microcrystalline ubiquitin using 2D (13)C-(13)C correlation spectroscopy under magic angle spinning conditions. High-resolution (13)C spectra have been acquired from hydrated microcrystals of site-directed (13)C-enriched ubiquitin. Inter-residue carbon-carbon distance constraints defining the global protein structure have been evaluated from 'dipolar-assisted rotational resonance' experiments recorded at various mixing times. Additional constraints on the backbone torsion angles have been derived from chemical shift analysis. Using both distance and dihedral angle constraints, the structure of microcrystalline ubiquitin has been refined to a root-mean-square deviation of about 1 A. The structure determination strategies for solid samples described herein are likely to be generally applicable to many proteins that cannot be studied by X-ray crystallography or solution NMR spectroscopy.Zech SG, Wand AJ, McDermott AE.Department of Chemistry, Columbia University, 3000 Broadway Mail Code 3113, New York, New York 10027, USA. Stephan.Zech@web.de. http://pubs.acs.org/cgi-bin/searchRedirect.cgi/jacsat/2005/127/i24/pdf/ja0503128.pdf
    Structure determination of aligned systems by solid-state NMR magic angle spinning methods
    Single crystal rotational echo double resonance (REDOR) experiments can be used to determine the three-dimensional orientation of heteronuclear bond vectors in an amino acid, as well as the crystal’s orientation relative to the rotor fixed frame (RFF). We also demonstrate that for samples uniaxially aligned along the rotor axis, the polar tilt angle of a bond vector relative to the RFF can be measured by use of an analytical expression that describes the REDOR curve for that system. These bond orientations were verified by X-ray indexing of the single crystal sample, and were shown to be as accurate as ±1°.Benjamin J. Gross, Joseph M. Tanski and Ann E. McDermott. Department of Chemistry, Columbia University, 3000 Broadway, New York, NY 10027, USADepartment of Chemistry, Vassar College, 124 Raymond Avenue, Poughkeepsie, NY 12604, USA http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6WJX-4GSJXTR-1-21&_cdi=6890&_user=699445&_orig=search&_coverDate=10%2F31%2F2005&_sk=998239997&view=c&wchp=dGLbVzb-zSkWW&md5=ea62baa31b9b7def622b18159285ca1d&ie=/sdarticle.pdf
    Chlorine-35/37 NMR spectroscopy of solid amino acid hydrochlorides: refinement of hydrogen-bonded proton positions using experiment and theory.
    Trends in the chlorine chemical shift (CS) tensors of amino acid hydrochlorides are investigated in the context of new data obtained at 21.1 T and extensive quantum chemical calculations. The analysis of chlorine-35/37 NMR spectra of solid L-tryptophan hydrochloride obtained at two magnetic field strengths yields the chlorine electric field gradient (EFG) and CS tensors, and their relative orientations. The chlorine CS tensor is also determined for the first time for DL-arginine hydrochloride monohydrate. The drastic influence of 1H decoupling at 21.1 T on the spectral features of salts with particularly small 35Cl quadrupolar coupling constants (CQ) is demonstrated. The chlorine CS tensor spans (Omega) of hydrochloride salts of hydrophobic amino acids are found to be larger than those for salts of hydrophilic amino acids. A new combined experimental-theoretical procedure is described in which quantum chemical geometry optimizations of hydrogen-bonded proton positions around the chloride ions in a series of amino acid hydrochlorides are cross-validated against the experimental chlorine EFG and CS tensor data. The conclusion is reached that the relatively computationally inexpensive B3LYP/3-21G* method provides proton positions which are suitable for subsequent higher-level calculations of the chlorine EFG tensors. The computed value of is less sensitive to the proton positions. Following this cross-validation procedure, /CQ(35Cl)/ is generally predicted within 15% of the experimental value for a range of HCl salts. The results suggest the applicability of chlorine NMR interaction tensors in the refinement of proton positions in structurally similar compounds, e.g., chloride ion channels, for which neutron diffraction data are unavailable. Bryce DL, Sward GD.Department of Chemistry and Centre for Catalysis Research and Innovation, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada. J Phys Chem B Condens Matter Mater Surf Interfaces Biophys. 2006 Dec 28;110(51):26461-70.
    Characterization of Folding Intermediates of a Domain-Swapped Protein by Solid-State NMR Spectroscopy.
    We have employed two-dimensional solid-state NMR to study structure and dynamics of insoluble folding states of the domain-swapped protein Crh. Starting from the protein precipitated at its pI, conformational changes due to a modest temperature increase were investigated at the level of individual residues and in real-time. As compared to the crystalline state, Crh pI-precipitates exhibited a higher degree of molecular mobility for several regions of the protein. A rigidly intact center was observed including a subset of residues of the hydrophobic core. Raising the temperature by 13 K to 282 K created a partially unfolded intermediate state that was converted into &bgr;-sheet-rich aggregates that are mostly of spherical character according to electron microscopy. Residue-by-residue analysis indicated that two out of three &agr;-helices in aggregated Crh underwent major structural rearrangements while the third helix was preserved. Residues in the hinge region exhibited major chemical-shift changes, indicating that the domain swap was not conserved in the aggregated form. Our study provides direct evidence that protein aggregates of a domain-swapped protein retain a significant fraction of native secondary structure and demonstrates that solid-state NMR can be used to directly monitor slow molecular folding events. Etzkorn M, Bockmann A, Penin F, Riedel D, Baldus M.Contribution from the Departments of NMR-Based Structural Biology and Electron Microscopy, Max-Planck-Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Gottingen, Germany, and Institut de Biologie et Chimie des Proteines, UMR 5086 CNRS-Universite Lyon 1, IFR128 BioSciences Lyon-Gerland, 7, passage du Vercors, 69367 Lyon, France.J Am Chem Soc. 2007 Jan 10;129(1):169-175.
    Three structural roles for water in bone observed by solid-state NMR.
    Hydrogen-bearing species in the bone mineral environment were investigated using solid-state NMR spectroscopy of powdered bone, deproteinated bone, and B-type carbonated apatite. Using magic-angle spinning and cross-polarization techniques three types of structurally-bound water were observed in these materials. Two of these water types occupy vacancies within the apatitic mineral crystal in synthetic carbonated apatite and deproteinated bone and serve to stabilize these defect-containing crystals. The third water was observed at the mineral surface in unmodified bone but not in deproteinated bone, suggesting a role for this water in mediating mineral-organic matrix interactions. Direct evidence of monohydrogen phosphate in a (1)H NMR spectrum of unmodified bone is presented for the first time. We obtained clear evidence for the presence of hydroxide ion in deproteinated bone by (1)H MAS NMR. A (1)H-(31)P heteronuclear correlation experiment provided unambiguous evidence for hydroxide ion in unmodified bone as well. Hydroxide ion in both unmodified and deproteinated bone mineral was found to participate in hydrogen bonding with neighboring water molecules and ions. In unmodified bone mineral hydroxide ion was found, through a (1)H-(31)P heteronuclear correlation experiment, to be confined to a small portion of the mineral crystal, probably the internal portion. Wilson EE, Awonusi A, Morris MD, Kohn DH, Tecklenburg MM, * Beck LW.Department of Chemistry, University of Michigan, Ann Arbor, USA. Biophys J. 2006 May 15;90(10):3722-31.
    3-Methylglutaric acid as a (13)C solid-state NMR standard.
    The calibration of a solid-state NMR spectrometer requires setting the magic angle, setting the reference and decoupler frequencies, ensuring that the magnetic field is homogeneous across the sample volume, optimizing the signal-to-noise ratio, determining the pi/2 pulse durations, and optimizing the Hartman-Hahn matching condition. Each task has one or more widely accepted standards, such as potassium bromide for setting the magic angle, adamantane for optimizing magnet homogeneity, and hexamethylbenzene or glycine for measuring the signal-to-noise ratio. We show that all of these tasks can be performed using 3-methylglutaric acid (MGA). In the case of high-powered decoupling, the CH(2) and CH carbon peaks of MGA provide an opportunity to evaluate the decoupling in a manner that is superior to any of the commonly used standard compounds. Thus, MGA can be used as a single solid-state NMR standard compound to perform all calibration steps except for magnet shimming. Barich DH, Gorman EM, Zell MT, Munson EJ. Department of Pharmaceutical Chemistry, University of Kansas, 2095 Constant Ave., Lawrence, KS 66047, USA. Solid State Nucl Magn Reson. 2006 Oct;30(3-4):125-9.
    Characterization of Folding Intermediates of a Domain-Swapped Protein by Solid-State NMR Spectroscopy.
    We have employed two-dimensional solid-state NMR to study structure and dynamics of insoluble folding states of the domain-swapped protein Crh. Starting from the protein precipitated at its pI, conformational changes due to a modest temperature increase were investigated at the level of individual residues and in real-time. As compared to the crystalline state, Crh pI-precipitates exhibited a higher degree of molecular mobility for several regions of the protein. A rigidly intact center was observed including a subset of residues of the hydrophobic core. Raising the temperature by 13 K to 282 K created a partially unfolded intermediate state that was converted into &bgr;-sheet-rich aggregates that are mostly of spherical character according to electron microscopy. Residue-by-residue analysis indicated that two out of three &agr;-helices in aggregated Crh underwent major structural rearrangements while the third helix was preserved. Residues in the hinge region exhibited major chemical-shift changes, indicating that the domain swap was not conserved in the aggregated form. Our study provides direct evidence that protein aggregates of a domain-swapped protein retain a significant fraction of native secondary structure and demonstrates that solid-state NMR can be used to directly monitor slow molecular folding events. Etzkorn M, Bockmann A, Penin F, Riedel D, Baldus M. Contribution from the Departments of NMR-Based Structural Biology and Electron Microscopy, Max-Planck-Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Gottingen, Germany, and Institut de Biologie et Chimie des Proteines, UMR 5086 CNRS-Universite Lyon 1, IFR128 BioSciences Lyon-Gerland, 7, passage du Vercors, 69367 Lyon, France. J Am Chem Soc. 2007 Jan 10;129(1):169-175.Click here to read
    51V Solid-State Magic Angle Spinning NMR Spectroscopy of Vanadium Chloroperoxidase.
    We report 51V solid-state NMR spectroscopy of the 67.5-kDa vanadium chloroperoxidase, at 14.1 T. We demonstrate that, despite the low concn. of vanadium sites in the protein (one per mol., 1 mmol of vanadium spins in the entire sample), the spinning sideband manifold spanning the central and the satellite transitions is readily detectable. The quadrupolar and chem. shift anisotropy tensors have been detd. by numerical simulations of the spinning sideband envelopes and the line shapes of the individual spinning sidebands corresponding to the central transition. The obsd. quadrupolar coupling const. Cq of 10.5 ± 1.5 MHz and chem. shift anisotropy ds of -520 ± 13 ppm are sensitive reporters of the geometric and electronic structure of the vanadium center. D. functional theory calcns. of the NMR spectroscopic observables for an extensive series of active site models indicate that the vanadate cofactor is most likely anionic with one axial hydroxo- group and an equatorial plane consisting of one hydroxo- and two oxo- groups. The work reported in this manuscript is the first example of 51V solid-state NMR spectroscopy applied to probe the vanadium center in a protein directly. This approach yields the detailed coordination environment of the metal unavailable from other exptl. measurements and is expected to be generally applicable for studies of diamagnetic vanadium sites in metalloproteins. Pooransingh-Margolis, Neela; Renirie, Rokus; Hasan, Zulfiqar; Wever, Ron; Vega, Alexander J.; Polenova, Tatyana. Brown Laboratories, Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, USA. Journal of the American Chemical Society (2006), 128(15), 5190-5208.
    Locating hydrogen atoms in single crystal and uniaxially aligned amino acids by solid-state NMR.
    We demonstrate a novel method to locate hydrogen atoms in amino acids, which involves measuring the C(alpha)H(alpha) bond vector geometry through orientationally dependent dipolar coupling frequencies measured by Lee-Goldburg cross polarization (LGCP). A 2D LGCP experiment is used to measure the polar angle of the C(alpha)H(alpha) bond vector in a single crystal of the model compound l-alanine. It is also demonstrated that by coupling the (13)C(alpha)(1)H(alpha) LGCP experiment to a (13)C(alpha)(15)N REDOR experiment, one can determine the complete three-dimensional geometry of the C(alpha)H(alpha) and C(alpha)N vectors in a single crystal. These measurements allow for location of hydrogen atoms in crystalline biological macromolecules.Benjamin J. Gross, Ann E. McDermott * Department of Chemistry, Columbia University, New York, NY 10027, USA.Journal of Magnetic Resonance 185 (2007) 12–18http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6WJX-4MGVPKM-1-28&_cdi=6890&_user=699476&_orig=search&_coverDate=12%2F04%2F2006&_sk=999999999&view=c&wchp=dGLzVzz-zSkWW&md5=e3555475bd570d9793cc65bcbfef260a&ie=/sdarticle.pdf
    Magic-Angle Spinning NMR Studies of Cell Wall Bound Aromatic-Aliphatic Biopolyesters Associated with Strengthening of Intercellular Adhesion in Potato (Solanum tuberosum L.) Tuber Parenchyma.
    Intercellular adhesion strengthening, a phenomenon that compromises the texture and the edible quality of potatoes (Solanum tuberosum), has been induced reproducibly by exposure to low-pH acetic acid solns. under tissue culture conditions. The resulting parenchyma tissues have been examd. by solid-state NMR in order to characterize the biopolymer(s) thought to be assocd. with this syndrome. Cross polarization-magic angle spinning (CPMAS) 13C NMR has been used to establish the presence of a polyphenol-suberin-like arom.-aliph. polyester within an abundant cell wall polysaccharide matrix in potato tubers that exhibit hardening due to strengthened intercellular adhesion. Dipolar dephasing and CP chem. shift anisotropy expts. suggest that the arom. domain is composed primarily of guaiacyl and sinapyl groups. Two-dimensional wide-line sepn. expts. show that the biopolymer assocd. with parenchyma hardening contains rigid polysaccharide cell walls and mobile aliph. long-chain fatty acids; 1H spin diffusion expts. show that these flexible aliph. chains are proximal to both the phenolics and a subpopulation of the cell wall polysaccharides. Finally, high-resoln. MAS NMR of parenchyma samples swelled in DMSO in conjunction with two-dimensional through-bond and through-space NMR spectroscopy provides evidence for covalent linkages among the polysaccharide, phenolic, and aliph. domains of the intercellular adhesion-strengthening biopolymer in potato parenchyma tissue. Bingwu Yu, G. Vengadesan, Hsin Wang, Liana Jashi, Tatiana Yefremov, Shiying Tian, Victor Gaba, Ilan Shomer, and Ruth E. Stark* College of Staten Island, Department of Chemistry, City University of New York, Staten Island, NY, USA. Biomacromolecules (2006), 7(3), 937-944. Publisher: American Chemical Society.http://pubs.acs.org/cgi-bin/article.cgi/bomaf6/2006/7/i03/pdf/bm050812t.pdf
    A Solid-State NMR Study of the Dynamics and Interactions of Phenylalanine Rings in a Statherin Fragment Bound to Hydroxyapatite Crystals
    Abstract:Extracellular matrix proteins regulate hard tissue growth by acting as adhesion sites for cells, by triggering cell signaling pathways, and by directly regulating the primary and/or secondary crystallization of hydroxyapatite, the mineral component of bone and teeth. Despite the key role that these proteins play in the regulation of hard tissue growth in humans, the exact mechanism used by these proteins to recognize mineral surfaces is poorly understood. Interactions between mineral surfaces and proteins very likely involve specific contacts between the lattice and the protein side chains, so elucidation of the nature of interactions between protein side chains and their corresponding inorganic mineral surfaces will provide insight into the recognition and regulation of hard tissue growth. Isotropic chemical shifts, chemical shift anisotropies (CSAs), NMR line-width information, 13C rotating frame relaxation measurements, as well as direct detection of correlations between 13C spins on protein side chains and 31P spins in the crystal surface with REDOR NMR show that, in the peptide fragment derived from the N-terminal 15 amino acids of salivary statherin (i.e., SN-15), the side chain of the phenylalanine nearest the C-terminus of the peptide (F14) is dynamically constrained and oriented near the surface, whereas the side chain of the phenylalanine located nearest to the peptide's N-terminus (F7) is more mobile and is oriented away from the hydroxyapatite surface. The relative dynamics and proximities of F7 and F14 to the surface together with prior data obtained for the side chain of SN-15's unique lysine (i.e., K6) were used to construct a new picture for the structure of the surface-bound peptide and its orientation to the crystal surface. ames M. Gibson,# Jennifer M. Popham, Vinodhkumar Raghunathan, Patrick S. Stayton,* and Gary P. Drobny*Contribution from the Departments of Bioengineering and Chemistry, University of Washington, Seattle, Washington 98195 J. Am. Chem. Soc., 128 (16), 5364 -5370, 2006. http://pubs.acs.org/cgi-bin/abstract.cgi/jacsat/2006/128/i16/abs/ja056731m.html
    Accurate Measurements of 13C-13C J-Couplings in the Rhodopsin Chromophore by Double-Quantum Solid-State NMR Spectroscopy
    Abstract:A new double-quantum solid-state NMR pulse sequence is presented and used to measure one-bond 13C-13C J-couplings in a set of 13C2-labeled rhodopsin isotopomers. The measured J-couplings reveal a perturbation of the electronic structure at the terminus of the conjugated chain but show no evidence for protein-induced electronic perturbation near the C11-C12 isomerization site. This work establishes NMR methodology for measuring accurate 1JCC values in noncrystalline macromolecules and shows that the measured J-couplings may reveal local electronic perturbations of mechanistic significance. Wai Cheu Lai, Neville McLean, Axel Gansmüller, Michiel A. Verhoeven, Gian Carlo Antonioli, Marina Carravetta, Luminita Duma, Petra H. M. Bovee-Geurts, Ole G. Johannessen, Huub J. M. de Groot, Johan Lugtenburg, Lyndon Emsley, Steven P. Brown, Richard C. D. Brown, Willem J. DeGrip, and Malcolm H. Levitt*School of Chemistry, University of Southampton, SO17 1BJ Southampton, U.K., Leiden Institute of Chemistry, Gorlaeus Laboratories, P.O. Box 9502, NL-2300 RA Leiden, The Netherlands, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, NL-6500 HB Nijmegen, The Netherlands, Department of Physics, University of Warwick, Coventry CV4 7AL, U.K., Laboratoire de Chimie, UMR-5182 CNRS/ENS, Laboratoire de Recherche Conventionné du CEA (DSV 23V/DSM 0432), Ecole Normale Supérieure de Lyon, 69364 Lyon, France J. Am. Chem. Soc., 128 (12), 3878 -3879, 2006. http://pubs.acs.org/cgi-bin/abstract.cgi/jacsat/2006/128/i12/abs/ja0581604.html
    High-Field NMR Studies of Molecular Recognition and Structure-Function Relationships in Antimicrobial Piscidins at the Water-Lipid Bilayer Interface
    Abstract:High magnetic field solid-state NMR was performed on amphipathic cationic antimicrobial peptides from fish to characterize their secondary structure and orientation in hydrated phospholipid bilayers. High-resolution distance and orientational restraints on 13C- and 15N-labeled amidated piscidins 1 and 3 provided site-specific information establishing -helicity and an orientation parallel to the membrane surface. Few membrane-bound natural peptides with this topology have been structurally studied at high resolution in the presence of hydrated lipid bilayers. This orientation was foreseen since the partitioning of amphipathic cationic antimicrobial peptides at the water-bilayer interface allows for favorable peptide-lipid interactions, and it may be related to the mechanism of action. The enhanced resolution obtained at 900 MHz evidences a determinant advantage of ultra-high-field NMR for the structural determination of multiple-labeled peptides and proteins. Eduard Y. Chekmenev,# Shiela M. Jones, Yelena N. Nikolayeva, Breanna S. Vollmar, Tim J. Wagner, Peter L. Gor'kov,# William W. Brey,# McKenna N. Manion, Ken C. Daugherty, and Myriam Cotten*Department of Chemistry, Pacific Lutheran University, 1010 122d Street South, Tacoma, Washington 98447, and Center for Interdisciplinary Magnetic Resonance, National High Magnetic Field Laboratory, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310 J. Am. Chem. Soc., 128 (16), 5308 -5309, 2006. http://pubs.acs.org/cgi-bin/abstract.cgi/jacsat/2006/128/i16/abs/ja058385e.html
    Capturing Intermediate Structures of Alzheimer's -Amyloid, A(1-40), by Solid-State NMR Spectroscopy
    Abstract:Molecular structures of diffusible amyloid intermediates, commonly observed in misfolding of amyloid proteins into fibrils, have attracted broad interest because the intermediates may be potent neurotoxins responsible for amyloid diseases such as Alzheimer's disease (AD) and because the intermediate structures provide an experimental basis for defining the misfolding pathway. However, owing to the intrinsically unstable and noncrystalline nature of the systems, traditional approaches such as X-ray crystallography and solution NMR have been ineffective for elucidating molecular-level structures of the amyloid intermediates. We present a novel approach using solid-state NMR (SSNMR) that permitted the first site-resolved structural measurement of an intermediate species in fibril formation for a 40-residue Alzheimer's -amyloid peptide, A(1-40). In this approach, we combined detection of conformation and morphology changes by fluorescence spectroscopy and electron microscopy and quantitative structural examination for freeze-trapped intermediates by SSNMR. The results provide the initial evidence that a spherical amyloid intermediate of 15-30 nm in diameter exists prior to fibril formation of A(1-40) and that the intermediate involves well-ordered -sheets in the C-terminal and hydrophobic core regions. The SSNMR-based approach presented here could be applied to intermediate species of diverse amyloid proteins. Sandra Chimon and Yoshitaka Ishii Department of Chemistry, University of Illinois at Chicago, Chicago Illinois 60607 J. Am. Chem. Soc., 127 (39), 13472 -13473, 2005. http://pubs.acs.org/cgi-bin/abstract.cgi/jacsat/2005/127/i39/abs/ja054039l.html
    Structures of Staphylococcus aureus Cell-Wall Complexes with Vancomycin, Eremomycin, and Chloroeremomycin Derivatives by 13C{19F} and 15N{19F} Rotational-Echo Double Resonance
    Abstract Solid-state NMR has been used to examine isolated cell walls and intact whole cells of Staphylococcus aureus complexed to five different vancomycin, eremomycin, and chloroeremomycin derivs. The cell walls and whole cells were specifically labeled with D-[1-13C]alanine, or a combination of [1-13C]glycine and [e-15N]lysine. Each of the bound glycopeptides had a 19F-labeled substituent at either its C-terminus or its disaccharide position. The 13C{19F} rotational-echo double-resonance (REDOR) dephasing for the cell-wall 13C-labeled bridging pentaglycyl segment connecting a glycopeptide-complexed peptidoglycan stem with its neighboring stem indicates that the fluorine labels for all bound glycopeptides are positioned at one or the other end of the bridge. An exception is N'-(p-trifluoromethoxybenzyl)chloroeremomycin, whose hydrophobic substituent differs in length by one Ph group compared to that of oritavancin, N'-4-[(4-chlorophenyl)benzyl)]chloroeremomycin. For this drug, the fluorine label is near the middle of the pentaglycyl segment. 15N{19F} REDOR dephasing shows the proximity of the fluorine to the bridge-link site of the pentaglycyl bridge for C-terminus-substituted moieties and the cross-link site for disaccharide-substituted moieties. Full-echo REDOR spectra of cell-wall complexes from cells labeled by D-[1-13C]alanine (in the presence of an alanine racemase inhibitor) reveal three different carbonyl carbon chem.-shift environments, arising from the D-Ala-D-Ala binding site and the D-Ala-Gly-1 cross-link site. The REDOR results indicate a single fluorine dephasing center in each peptidoglycan complex. Mol. models of the mature cell-wall complexes that are consistent with internuclear distances obtained from 13C{19F} and 15N{19F} REDOR dephasing allow a correlation of structure and antimicrobial activity of the glycopeptides. Kim, Sung Joon; Cegelski, Lynette; Preobrazhenskaya, Maria; Schaefer, Jacob. Department of Molecular Biophysics, Washington University School of Medicine, St. Louis, MO, USA. Biochemistry (2006), 45(16), 5235-5250. http://pubs.acs.org/cgi-bin/abstract.cgi/bichaw/2006/45/i16/abs/bi052660s.html
    Quantitative Analysis of Backbone Dynamics in a Crystalline Protein from Nitrogen-15 Spin-Lattice Relaxation
    Abstract:A detailed analysis of nitrogen-15 longitudinal relaxation times in microcrystalline proteins is presented. A theoretical model to quantitatively interpret relaxation times is developed in terms of motional amplitude and characteristic time scale. Different averaging schemes are examined in order to propose an analysis of relaxation curves that takes into account the specificity of MAS experiments. In particular, it is shown that magic angle spinning averages the relaxation rate experienced by a single spin over one rotor period, resulting in individual relaxation curves that are dependent on the orientation of their corresponding carousel with respect to the rotor axis. Powder averaging thus leads to a nonexponential behavior in the observed decay curves. We extract dynamic information from experimental decay curves, using a diffusion in a cone model. We apply this study to the analysis of spin-lattice relaxation rates of the microcrystalline protein Crh at two different fields and determine differential dynamic parameters for several residues in the protein. Nicolas Giraud, Martin Blackledge, Maurice Goldman, Anja Böckmann, Anne Lesage, François Penin, and Lyndon Emsley*Contribution from the Laboratoire de Chimie (UMR 5182 CNRS/ENS Lyon), Laboratoire de Recherche Conventionné du CEA (DSV 23V/DSM 0432), Ecole Normale Supérieure de Lyon, Lyon, France, Institut de Biologie Structurale Jean Pierre Ebel (CNRS/CEA/UJF), 41 rue Jules Horowitz, 38027 Grenoble, France, CEA Saclay, DSM/DRECAM/Service de Physique de l'Etat Condensé, F-91191 Gif sur Yvette, France, and Laboratoire de Conformation des Protéines (UMR 5086 IBCP/CNRS), Institut de Biologie et Chimie des Protéines, Lyon, France J. Am. Chem. Soc., 127 (51), 18190 -18201, 2005. http://pubs.acs.org/cgi-bin/abstract.cgi/jacsat/2005/127/i51/abs/ja055182h.html
    Three Structural Roles for Water in Bone Observed by Solid-State NMR
    Hydrogen-bearing species in the bone mineral environment were investigated using solid-state NMR spectroscopy of powdered bone, deproteinated bone, and B-type carbonated apatite. Using magic-angle spinning and cross-polarization techniques three types of structurally-bound water were observed in these materials. Two of these water types occupy vacancies within the apatitic mineral crystal in synthetic carbonated apatite and deproteinated bone and serve to stabilize these defect-containing crystals. The third water was observed at the mineral surface in unmodified bone but not in deproteinated bone, suggesting a role for this water in mediating mineral-organic matrix interactions. Direct evidence of monohydrogen phosphate in a 1H NMR spectrum of unmodified bone is presented for the first time. We obtained clear evidence for the presence of hydroxide ion in deproteinated bone by 1H MAS NMR. A 1H-31P heteronuclear correlation experiment provided unambiguous evidence for hydroxide ion in unmodified bone as well. Hydroxide ion in both unmodified and deproteinated bone mineral was found to participate in hydrogen bonding with neighboring water molecules and ions. In unmodified bone mineral hydroxide ion was found, through a 1H-31P heteronuclear correlation experiment, to be confined to a small portion of the mineral crystal, probably the internal portion. Erin E. Wilson *, Ayorinde Awonusi {dagger}, Michael D. Morris *, David H. Kohn {ddagger} §, Mary M. J. Tecklenburg {dagger} and Larry W. Beck ** Department of Chemistry, and § Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan; {dagger} Department of Chemistry, Central Michigan University, Mt. Pleasant, Michigan; and {ddagger} Department of Biologic and Materials Sciences, University of Michigan Dental School, Ann Arbor, Michigan Biophysical Journal (2006), 90(10), 3722-3731. http://www.biophysj.org/cgi/content/abstract/90/10/3722
    Multiple-sample probe for solid-state NMR studies of pharmaceuticals
    Abstract: Solid-state NMR spectroscopy (SSNMR) is an extremely powerful technique for the analysis of pharmaceutical dosage forms. A major limitation of SSNMR is the number of samples that can be analyzed in a given period of time. A solid-state magic-angle spinning (MAS) probe that can simultaneously acquire up to seven SSNMR spectra is being developed to increase throughput/signal-to-noise ratios. A prototype probe incorporating two MAS modules has been developed and spectra of ibuprofen and aspirin have been acquired simultaneously. This version is limited to being a two-module probe due to large amounts of space required for the tuning elements located next to the MAS modules. A new probe design incorporating coaxial transmission lines and smaller MAS modules has been constructed. This probe allows for close proximity of the MAS modules (within 3 cm), adequate proton decoupling power (>50 kHz), and the capability of remote tuning and sample changing. Spectra of hexamethylbenzene (HMB) have been acquired and show signal-to-noise ratios comparable to existing SSNMR probes. Adamantane line widths are also comparable to conventional probe technology. Decoupling powers of 70 kHz have been achieved using a MAS module suitable for 3 cm spacing between modules. Remote tuning has also been achieved with this new coaxial transmission line design. This probe design can be easily scaled to incorporate multiple MAS modules, which is a limitation of the previous design. The number of modules that can be incorporated is only limited by the number of transmission lines that will fit in a cross-sectional diameter of the bore and the axial field length of the magnet. Nelson, Benjamin N.; Schieber, Loren J.; Barich, Dewey H.; Lubach, Joseph W.; Offerdahl, Thomas J.; Lewis, David H.; Heinrich, John P.; Munson, Eric J. Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, KS, USA. Solid State Nuclear Magnetic Resonance (2006), 29(1-3), 204-213. http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6THK-4HD8B7X-1&_coverDate=02%2F28%2F2006&_alid=401700358&_rdoc=1&_fmt=&_orig=search&_qd=1&_cdi=5285&_sort=d&view=c&_acct=C000039279&_version=1&_urlVersion=0&_userid=699476&md5=e1d657b931b187f92125f29328a91eec
    Zinc Solid-State NMR Spectroscopy of Human Carbonic Anhydrase: Implications for the Enzymatic Mechanism
    Abstract:The pH dependence of the 67Zn solid-state nuclear magnetic resonance spectroscopy of human carbonic anhydrase (CAII) has been investigated to characterize the nature of the fourth ligand. CAII, through the Zn2+-bound hydroxide, catalyzes the deceptively simple reaction: CO2 + H2O HCO3- + H+. The accepted mechanism for CAII would predict that water would be bound to the Zn2+ at pH 5 and hydroxide would be bound at pH 8.5. The measured values for the electric field gradient (EFG) or quadrupole coupling constant (Cq) for CAII are independent of pH within the limits of the experimental error, i.e., 9.8 ± 0.2 MHz. The EFG interaction has been predicted by ab initio electronic structure calculations for water and hydroxide bound to the zinc, including various levels of hydrogen bonding. After comparing the predicted Cq's with the experimental values, we conclude that the species present from pH 5-8.5 is the hydroxide form. The NMR data presented here is not consistent with the accepted mechanism for CAII. We show that the NMR data is consistent with an alternative mechanism of CAII. J. Am. Chem. Soc., 126 (14), 4735 -4739, 2004.Andrew S. Lipton, Robert W. Heck, and Paul D. Ellis*Contribution from the Macromolecular Structure & Dynamics Directorate, W. R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352 http://pubs.acs.org/cgi-bin/abstract.cgi/jacsat/2004/126/i14/abs/ja0305609.html
    Single-Crystal Studies of Peptide Prolyl and Glycyl 15N Shielding Tensors.
    Abstract:15N shielding tensors were determined for the central peptide groups in GGV, AGG, and APG by single-crystal NMR. We find that the angle between the downfield component (11) and the N-H or the N-C (pro) bonds is in the range of 20-23 and in accord with previous solid-state NMR measurements. However, AGG, unlike APG or GGV, has a distorted peptide plane, and 11 lies approximately in the plane of N, C, and H rather than in the peptide plane defined by heavy atoms. Accurate orientations of 22 and 33 were determined, and the usual assumption that 22 is along the peptide normal was found only in APG which has a highly nonaxial tensor. More generally, 22 and 33 are rotated about the 11 axis (36 in GGV). These results are compared with DFT calculations to gain a structural understanding of the effects of intermolecular interactions on shielding tensor principal components and orientations. Trimeric clusters containing H-bonded neighbors predict the orientations of the principal components within 2-3, but calculated principal components are less quantitative. Possible reasons for this disagreement are explored. J. Am. Chem. Soc., 127 (25), 9030 -9035, 2005.Kevin W. Waddell, Eduard Y. Chekmenev, and Richard J. Wittebort*Contribution from the Department of Chemistry, 2320 South Brook Street, University of Louisville, Louisville, Kentucky 40292 http://pubs.acs.org/cgi-bin/abstract.cgi/jacsat/2005/127/i25/abs/ja044204h.html
    Membrane permeabilization, orientation, and antimicrobial mechanism of subtilosin A
    Abstract: Subtilosin A is an antimicrobial peptide produced by the soil bacterium Bacillus subtilis that possesses bactericidal activity against a diverse range of bacteria, including Listeria monocytogenes. Recent structural studies have found that subtilosin A is posttranslationally modified in a unique way, placing it in a new class of bacteriocins. In this study, in order to understand the mechanism of membrane-disruption by subtilosin A, the interaction of the peptide with model phospholipid bilayers is characterized using fluorescence, solid-state NMR and differential scanning calorimetry (DSC) experiments. Our results in this study show that subtilosin A interacts with the lipid head group region of bilayer membranes in a concentration dependent manner. Fluorescence experiments reveal the interaction of subtilosin A with small unilamellar vesicles (SUVs) composed of POPC, POPG and E. coli total lipids, and that at least one edge of the molecule is buried in membrane bilayers. At high concentrations, it induces leakage from SUVs of POPC and POPE/POPG (7:3) mixture. 15N solid-state NMR data suggests that the cyclic peptide is partially inserted into bilayers, which is in agreement with the fluorescence data. 31P and 2H NMR experiments and DSC data support the hypothesis that subtilosin A adopts a partially buried orientation in lipid bilayers, by showing that it induces a conformational change in the lipid head group and disordering in the hydrophobic region of bilayers. These results suggest that the lipid perturbation observed in this study may be one of the consequences of subtilosin A binding to lipid bilayers, which results in membrane permeabilization at high peptide concentrations. Chemistry and Physics of Lipids (2005), 137(1-2), 38-51.Thennarasu, Sathiah; Lee, Dong-Kuk; Poon, Alan; Kawulka, Karen E.; Vederas, John C.; Ramamoorthy, Ayyalusamy. http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6T2N-4GNTCFS-1&_coverDate=10%2F31%2F2005&_alid=397849360&_rdoc=1&_fmt=&_orig=search&_qd=1&_cdi=4923&_sort=d&view=c&_acct=C000039279&_version=1&_urlVersion=0&_userid=699476&md5=8ae23b2abf031793e4f58cbd8cc585de
    In situ nuclear magnetic resonance investigations of lithium ions in carbon electrode materials using a novel detector
    Abstract. The reversible electrochemical process (insertion/extraction) of lithium ions in graphitic carbon was monitored in situ for the first time by 7Li nuclear magnetic resonance (NMR) spectroscopy using a novel NMR apparatus. The compression coin cell battery imager is a simple device that combines the functions of an electrochemical cell and an NMR detector. A series of 7Li NMR spectra obtained for a blend of spherical and flaky disordered graphitic carbon particles revealed two distinct chemical shift signatures for the lithium ions that were inserted and extracted in the first electrochemical cycle. The lithium signal at ~50 ppm is consistent with the interplane sites for lithium ions on the sixfold axis between two stacked aromatic carbon rings aligned in registry. The second predominant lithium signal at ~12 ppm occurs in the chemical shift region reported for high-stage lithiated graphite and a dispersion of lithium-ion sites found in disordered carbon matrices. In addition, we observed chemical shift signatures similar to those assigned to Li-7 nuclei in lithium oxide, lithium carbonate, lithium alkyls, and lithium alkoxides that occur near 0 ppm and represent lithium nuclei that are irreversibly bound in the electrode/electrolyte interphase. An increase in intensity in the spectral region that is normally associated with irreversibly bound lithium was observed during the first discharge cycle, as anticipated. However, the same peaks in the spectrum unexpectedly diminished during the subsequent charge cycle, suggesting that the interphase between the carbon electrode and the electrolyte is built up over several cycles.J. Phys.: Condens. Matter 13 8269-8285 Gerald, R. E, II; Sanchez, J.; Johnson, C. S.; Klingler, R. J.; Rathke, J. W.http://ejournals.ebsco.com/Direct.asp?AccessToken=7D9D9B00VFGVJ5YX9RXG-FGLV1B9N9D&Show=Object&ErrorURL=http%3A%2F%2Fchemport%2Ecas%2Eorg%2Fhtml%2Fenglish%2Febsco%5Ferror%2Ehtml
    Molecular Structure of fd (f1, M13) Filamentous Bacteriophage Refined with Respect to X-ray Fibre Diffraction and Solid-state NMR Data Supports Specific Models of Phage Assembly at the Bacterial Membrane
    Filamentous bacteriophage (Inovirus) is a simple and well-characterized model system. The phage particle, or virion, is about 60 Angstrom capital A, ring in diameter and several thousand angstrom units long. The virions are assembled at the bacterial membrane as they extrude out of the host without killing it, an example of specific transport of nucleoprotein assemblages across membranes. The Ff group (fd, f1 and M13) has been especially widely studied. Models of virion assembly have been proposed based on a molecular model of the fd virion derived by X-ray fibre diffraction. A somewhat different model of the fd virion using solid-state NMR data has been proposed, not consistent with these models of assembly nor with the X-ray diffraction data. Here we show that reinterpreted NMR data are also consistent with the model derived from X-ray fibre diffraction studies, and discuss models of virion assembly.Journal of Molecular Biology (2006), 355(2), 294-309.D.A. Marvina, Corresponding Author Contact Information, E-mail The Corresponding Author, L.C. Welsha, M.F. Symmonsa, W.R.P. Scottb and S.K. StrausbaDepartment of Biochemistry, University of Cambridge, Cambridge CB2 1GA, UKbDepartment of Chemistry, University of British Columbia, Vancouver BC, Canada V6T 1Z1 http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WK7-4HHH7F4-4&_coverDate=01%2F13%2F2006&_alid=397842592&_rdoc=1&_fmt=&_orig=search&_qd=1&_cdi=6899&_sort=d&view=c&_acct=C000039279&_version=1&_urlVersion=0&_userid=699476&md5=19087c4da5e7cc06f00cb12ed31aa1d5
    Structure and dynamics studies of BSP-24 to to investigate the role of bone sialoprotein II (BSP) in biomineralization.
    AbstractStructural studies of BSP and other related proteins have revealed little inherent structure thus far and the highly anionic nature of BSP precludes obtaining crystallog. data. BSP-24 is synthetic peptide comprised of what is thought to be the sequence that interacts with HAP in the collagen matrix during bone formation. Here solid-state NMR spectroscopy with magic angle spinning was used to examine structure/function relationships in interaction of various phosphorylated forms of BSP-24 with HAP. Using 13C enriched peptides and homonuclear dipolar recoupling expts. and relaxation measurements, the effect of phosphorylation on dynamics, structure and function of BSP-24 was studied. Isothermal titrn. calorimetry (ITC) binding assays were also used to assess the effect of phosphorylation on the energetics of BSP-24 binding to HAP. Abstracts of Papers, 231st ACS National Meeting, Atlanta, GA, United States, March 26-30, 2006 (2006), PHYS-412.Samuel-Landtiser, Mini S.; Chung, Alfred; Gower, Laurie B.; Long, Joanna R.. Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL, USA.
    NMR studies of modified nasicon-like, lithium conducting solid electrolytes*1
    Abstract27Al, 31P and 7Li NMR measurements have been performed on lithium conducting ceramics based on the LiTi2(PO4)3 structure with Al, V and Nb metal ions substituted for either Ti or P within the framework NASICON structure. The 27Al magic angle spinning NMR measurements have revealed that, although Al is intended to substitute for octahedral Ti sites, additional substitution into tetrahedral environments (presumably phosphorous sites) occurs with increasing amount of Al addition. This tetrahedral substitution appears to occur more readily in the presence of vanadium, in Li1+xAlxTi2−x(PO4)2.9(VO4)0.1, whereas similar niobium additions (in place of vanadium) appear to stifle tetrahedral substitution. 7Li static NMR spectra reveal quadrupolar structure with Cq approximately 42 kHz, largely independent of substitution. Measurement of the 7Li central transition linewidth at room temperature reveals a relatively mobile lithium species (300–900 Hz) with linewidth tending to decrease with Al substitution and increase with increasing V or Nb. This new structural information is discussed in the context of ionic conduction in these ceramics. Solid State Ionics (1999), 124, (3,4), 213-217.M. ForsythCorresponding Author Contact Information, E-mail The Corresponding Author, a, S. Wonga, K. M. Nairna, A. S. Bestb, P. J. Newmanb and D. R. MacFarlaneb http://www.chem.csi.cuny.edu/rcn/index.php?id=resources&subid=publication&mesg=Item%20Added
    Magnetic resonance studies of chemically intercalated Li[sub x]V[sub 2]O[sub 5] aerogels.
    Abstract: 7Li, 51V solid-state nuclear magnetic resonance ~NMR! and electron paramagnetic resonance ~EPR!measurements have been performed upon chemically lithiated LixV2O5 aerogels, with compositionsof 1.00,x,5.84. These compounds can intercalate reversibly large amounts of Li1 and, therefore,are of interest as battery cathodes. Still, the mechanism regarding the electron transfer from aninserted lithium metal to a host aerogel V2O5 and details regarding the lithium cation environmentsare not fully understood. LixV2O5 crystals are known to exhibit various structural phase changesand, when multiple phases are present, the capability of the material to intercalate reversibly appearsto be adversely affected. On the other hand, aerogels have no such multiphase behavior and aerogelbased cathodes exhibit greater stability upon cycling. NMR shows that neither the structure nor thedynamics vary greatly with the amount of lithium content, and that the lithiated aerogel is bestdescribed as a single-phase material. Characterization of lithium and vanadium sites is performedthrough analysis of both NMR and EPR spectra. 7Li line shapes are affected by first-orderquadrupolar, magnetic dipolar interactions and motional narrowing. At and above room temperature,relaxation is governed primarily by a quadrupolar mechanism. NMR derived activation energies anddiffusion coefficients are different from those of bronzes and electrochemically intercalated V2O5 .51V NMR lines, indicative of the presence of V51 at all compositions, undergo diamagnetic shiftsof up to about 50 ppm with an increase in lithium content. These results imply the presence ofoxidized impurities or electronic charge delocalization. Additionally, EPR measurements provideevidence of VO21 impurities and indirect evidence of nonbridging oxygen at high lithium contents.Journal of Applied Physics, 10/1/2002, Vol. 92 Issue 7, p3839, 14pAuthor(s):    Stallworth, P. E.; Johnson, F. S.; Greenbaum, S. G.; Passerini, S.; Flowers, J.; Smyrl, W.http://search.epnet.com/login.aspx?direct=true&db=aph&an=7355371
    Spectroscopic characterization of natural corals
    The FTIR, micro-Raman, NMR, and XPS spectra of 25 different natural corals have been compared. Reflectance and transmission absorbance IR and Raman data have been used as rapid and efficient means of classification of natural corals containing aragonite (non-precious white species), calcite (red, pink, precious white species), and organic material (black protein polymer). The combination of reflectance IR and infrared microscopy could serve as a rapid, non-destructive method for distinguishing natural corals from artificial, fake jewels.Anal Bioanal Chem (2003) 377 : 1032–1037B. Kaczorowska1, A. Hacura1 Contact Information, T. Kupka1, 2, R. Wrzalik1, E. Talik1, G. Pasterny1 and A. Matuszewska3(1)     Institute of Physics, Silesian University, 4 Uniwersytecka St, 40-007 Katowice, Poland(2)     Center of Polymer Chemistry, Polish Academy of Sciences, 34 M. Curie-Sklodowska St, 41-800 Zabrze, Poland(3)     Faculty of Earth Sciences, University of Silesia, 60 Beogondzinacuteska St, 41-200 Sosnowiec, Polandhttp://springer.metapress.com/media/49tewvrhmq5xgrykklby/contributions/f/x/4/b/fx4by65ydly5m8cg.pdf
    Broadband Homonuclear Correlation Spectroscopy at High Magnetic Fields and MAS Frequencies
    We present a new homonuclear recoupling sequence, CMAR, that allows observation of 2D 13C-13C correlation spectra at high magnetic fields and MAS frequencies (10-30 kHz). The main advantages of the sequence are that it provides efficient, broadband dipolar recoupling and concurrently decouples the 1H spins from the 13C's. Thus, no additional 1H decoupling is required during the mixing period, thereby significantly reducing the radio frequency power requirements for the experiment. Thus, CMAR significantly extends the range of applicability of the usual homonuclear recoupling techniques and should be of major interest for structure determinations of biomolecules at high magnetic fields.J. Am. Chem. Soc., 128 (6), 1776 -1777, 2006.Gaël De Paëpe, Marvin J. Bayro, Józef Lewandowski, and Robert G. Griffin*Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 http://pubs.acs.org/cgi-bin/abstract.cgi/jacsat/2006/128/i06/abs/ja0550430.html
    Multi-dimensional pulsed field gradient magic angle spinning NMR experiments on membranes
    The benefits of gradient techniques in the study of lipid membranes are demonstrated on a sample of 1-palmitoyl-2-oleoyl-sn-glycero-3 phosphocholine (POPC) liposomes embedded with ibuprofen. Most techniques from gradient NMR spectroscopy on solution samples are directly applicable to membrane samples subjected to magic angle spinning (MAS). Gradient-enhanced homo- and heteronuclear chemical shift correlation techniques were used to make resonance assignments. Gradient NOESY experiments provide insight into the location and dynamics of lipids, ibuprofen and water. Application of gradients not only reduces experiment time but also the t1 noise in the multi-dimensional spectra. Diffusion measurements with pulsed field gradients characterize lateral movements of lipid and drug molecules in membranes. The theoretical framework for data analysis of MAS diffusion experiments on randomly oriented multilamellar liposomes is presented. Published in 2004 by John Wiley & Sons, Ltd.Magn. Reson. Chem. 2004; 42: 115–122Holly C. Gaede, Klaus Gawrisch *Laboratory of Membrane Biochemistry and Biophysics, NIAAA, NIH, 12420 Parklawn Drive, Rockville, Maryland 20852, USAhttp://www3.interscience.wiley.com/cgi-bin/abstract/106601051/ABSTRACT?CRETRY=1&SRETRY=0
    Using Switched Angle Spinning to Simplify NMR Spectra of Strongly Oriented Samples
    This contribution describes a method that manipulates the alignment director of a liquid crystalline sample to obtain anisotropic magnetic interaction parameters, such as dipolar coupling, in an oriented liquid crystalline sample. By changing the axis of rotation with respect to the applied magnetic field in a spinning liquid crystalline sample, the dipolar couplings present in a normally complex strong coupling spectrum are scaled to a simple weak coupling spectrum. This simplified weak coupling spectrum is then correlated with the isotropic chemical shift in a switched angle spinning (SAS) two-dimensional (2D) experiment. This dipolar-isotropic 2D correlation was also observed for the case where the couplings are scaled to a degree where the spectrum approaches strong coupling. The SAS 2D correlation of C6F5Cl in the nematic liquid crystal I52 was obtained by first evolving at an angle close to the magic angle (54.7) and then directly detecting at the magic angle. The SAS method provides a 2D correlation where the weak coupling pairs are revealed as cross-peaks in the indirect dimension separated by the isotropic chemical shifts in the direct dimension. Additionally, by using a more complex SAS method which involves three changes of the spinning axis, the solidlike spinning sideband patterns were correlated with the isotropic chemical shifts in a 2D experiment. These techniques are expected to enhance the interpretation and assignment of anisotropic magnetic interactions including dipolar couplings for molecules dissolved in oriented liquid crystalline phases.J. Am. Chem. Soc., 125 (26), 7998 -8006, 2003.Robert H. Havlin,* Gregory H. J. Park, Tanya Mazur, and Alexander PinesContribution from the Materials Sciences Division, Lawrence Berkeley National Laboratory, and Department of Chemistry, University of California, Berkeley, California 94720 http://pubs.acs.org/cgi-bin/abstract.cgi/jacsat/2003/125/i26/abs/ja0342244.html
    Probing Specific Lipid-Protein Interaction by Saturation Transfer Difference NMR Spectroscopy
    We studied the interaction of mono- and polyunsaturated phosphatidylcholines with rhodopsin by 1H NMR saturation transfer difference spectroscopy with magic angle spinning (STD-MAS NMR). The results indicate a strong preference for interaction of rhodopsin with the polyunsaturated docosahexaenoic acid.J. Am. Chem. Soc., 127 (38), 13110 -13111, 2005.Olivier Soubias and Klaus Gawrisch*Laboratory of Membrane Biochemistry and Biophysics, NIAAA, National Institutes of Health, Bethesda, Maryland 20892 http://pubs.acs.org/cgi-bin/abstract.cgi/jacsat/2005/127/i38/abs/ja0538942.html
    Direct Characterization of the Folded, Unfolded and Urea-denatured States of the C-terminal Domain of the Ribosomal Protein L9
    The stability of the isolated C-terminal domain of the ribosomal protein L9 (CTL9) is strongly dependent upon pH. Below pH 4.2, the folded and unfolded states are both populated significantly. Their interconversion is slow on the NMR chemical shift time-scale and separate, well-resolved resonances from each state are observed. This allows the hydrodynamic properties of both states to be studied under identical conditions by using pulse field gradient NMR experiments. Hydrodynamic radii of the folded, unfolded and urea denatured protein molecules at pD 3.8 have been derived. The acid-denatured protein has a significantly smaller hydrodynamic radius, 28.2 , compared to that of the urea-denatured protein, which is 33.6 at pD 3.8. Far-UV CD spectra show that there is more residual secondary structure retained in the acid-denatured ensemble than in the urea-denatured one. ANS binding experiments and analysis of the CD data show that this acid-denatured species is not a molten globule state. Diffusion measurements of CTL9 were conducted over the pD range from 2.1 to 7.0. The hydrodynamic radii of both the folded and the acid-unfolded protein start to increase below pD 4, with the radius of hydration of the acid-unfolded state increasing from 25.1 at pD 4.2 to 33.5 at pD 2.1. The hydrodynamic radius of the urea-denatured protein is much less sensitive to pH. The unfolded protein at pD 2.1, no urea, has almost the same hydrodynamic radius as the urea-denatured protein at pD 3.8. The CD spectra, however, show significant differences in residual secondary structure, and the acid-denatured state contains more structure. J. Mol. Biol. (2005) 349, 839–846Ying Lia, Francis Picarta and Daniel P. Raleigha, b, , aDepartment of Chemistry, State University of New York at Stony Brook, Stony Brook, NY, 11794-3400, USAbGraduate Program in Biochemistry and Structural Biology, and Graduate Program in Biophysics, State University of New York at Stony Brook, Stony Brook, NY, 11794, USA http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WK7-4G1R0M0-3&_coverDate=06%2F17%2F2005&_alid=390532707&_rdoc=1&_fmt=&_orig=search&_qd=1&_cdi=6899&_sort=d&view=c&_acct=C000039279&_version=1&_urlVersion=0&_userid=699476&md5=8130fc840c6000cea1c5d59ce6f60d22
    Accurate Measurements of 13C-13C J-Couplings in the Rhodopsin Chromophore by Double-Quantum Solid-State NMR Spectroscopy
    A new double-quantum solid-state NMR pulse sequence is presented and used to measure one-bond 13C-13C J-couplings in a set of 13C2-labeled rhodopsin isotopomers. The measured J-couplings reveal a perturbation of the electronic structure at the terminus of the conjugated chain but show no evidence for protein-induced electronic perturbation near the C11-C12 isomerization site. This work establishes NMR methodology for measuring accurate 1JCC values in noncrystalline macromolecules and shows that the measured J-couplings may reveal local electronic perturbations of mechanistic significance.J. Am. Chem. Soc., 128 (12), 3878 -3879, 2006.Wai Cheu Lai, Neville McLean, Axel Gansmüller, Michiel A. Verhoeven, Gian Carlo Antonioli, Marina Carravetta, Luminita Duma, Petra H. M. Bovee-Geurts, Ole G. Johannessen, Huub J. M. de Groot, Johan Lugtenburg, Lyndon Emsley, Steven P. Brown, Richard C. D. Brown, Willem J. DeGrip, and Malcolm H. Levitt*School of Chemistry, University of Southampton, SO17 1BJ Southampton, U.K., Leiden Institute of Chemistry, Gorlaeus Laboratories, P.O. Box 9502, NL-2300 RA Leiden, The Netherlands, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, NL-6500 HB Nijmegen, The Netherlands, Department of Physics, University of Warwick, Coventry CV4 7AL, U.K., Laboratoire de Chimie, UMR-5182 CNRS/ENS, Laboratoire de Recherche Conventionné du CEA (DSV 23V/DSM 0432), Ecole Normale Supérieure de Lyon, 69364 Lyon, France http://pubs.acs.org/cgi-bin/abstract.cgi/jacsat/2006/128/i12/abs/ja0581604.html
    Val659Glu Mutation within the Transmembrane Domain of ErbB-2: Effects Measured by 2H NMR in Fluid Phospholipid Bilayers
    Certain point mutations within the hydrophobic transmembrane domains of class I receptor tyrosine kinases have been associated with oncogenic transformation in vitro and in vivo [Gullick, J., and Srinivasan, R. (1998) Breast Cancer Res. Treat. 52, 43-53]. An important example is the replacement of a single (hydrophobic) valine by (charged) glutamate in the rat protein, Neu, and in the homologous human protein, ErbB-2. It has been suggested that the oncogenic nature of this ValGlu substitution may derive from alteration of the transmembrane domain's ability to take part in direct side-to-side associations. In the present work, we examined the basis of this phenomenon by studying transmembrane portions of ErbB-2 in fluid bilayer membranes. An expression system was designed to produce such peptides from the wild-type ErbB-2, and from an identical region of the transforming mutant in which Val659 is replaced by Glu. All peptides were 50-mers, containing the appropriate transmembrane domain plus contiguous stretches of amino acids from the cytoplasmic and extracellular domains. Deuterium heteronuclear probes were incorporated into alanine side chains (thus, each alanine -CH3 side chain became -CD3). Given the presence of natural alanine residues at positions 648 and 657 within ErbB-2, this approach afforded heteronuclear probes within the motif Ser656AlaValValGlu660, thought to be important for homodimer formation, and nine residues upstream of this site. Further peptides were produced, by site-directed mutagenesis, to confirm spectral assignments and to provide an additional probe location at position 670 (11 residues downstream of the motif region). On SDS-polyacrylamide gels, the transmembrane peptides migrated as predominant monomers in equilibrium with smaller populations of homodimers/-oligomers. CD spectra of both wild-type and transforming mutant peptides were consistent with the transmembrane portions being basically -helical. 2H NMR spectra of each transmembrane peptide were obtained in fluid phospholipid bilayers of 1-palmitoyl-2-oleoylphosphatidylcholine (POPC) from 35 to 65 C. Results were consistent with the concept that the glutamic acid residue characterizing the mutant is uncharged at neutral pH. Narrowed spectral components from species rotating rapidly and symmetrically within the membrane appeared to represent monomeric peptide. Mutation of Val659 to Glu within the hydrophobic domain induced changes in side chain angulation of at least 6-8 at Ala657 (i.e., within the five amino acid motif thought to be involved in homodimer formation), and downstream of this site to residue 670. There was little evidence of effect at the upstream site (Ala648) at the membrane surface. This result argues that the transforming mutation is associated with significant intramolecular rearrangement of the monomeric transmembrane helix-extending over some four helix turns-which could influence its lateral associations. In addition, temperature effects on spectral quadrupole splittings suggested that there is greater peptide backbone flexibility for the wild-type transmembrane region.Biochemistry, 39 (21), 6572 -6580, 2000.Simon Sharpe, Kathryn R. Barber, and Chris W. M. Grant*Department of Biochemistry, University of Western Ontario, London, Ontario N6A 5C1, Canada http://pubs.acs.org/cgi-bin/abstract.cgi/bichaw/2000/39/i21/abs/bi000038o.html
    Interaction of the Neuropeptide Met-Enkephalin with Zwitterionic and Negatively Charged Bicelles as Viewed by 31P and 2H Solid-State NMR
    The interaction of the neuropeptide methionine-enkephalin (Menk) with bicelles was investigated by solid-stateNMR. Bicelles composed of dimyristoylphosphatidylcholine (DMPC) and dicaproylphosphatidylcholine (DCPC) were modifiedto investigate the effect of the lipid headgroup and electrostatic charges on the association with Menk. A total of 10 mol % ofDMPC was replaced by zwitterionic phosphatidylethanolamine (DMPE), anionic phosphatidylglycerol (DMPG), or phosphatidylserine(DMPS). The preparation of DMPE-doped bicelles (Bic/PE) is reported for the first time. The 31P and 2H NMR resultsrevealed changes in the lipid dynamics when Menk interacts with the bicellar systems. 2H NMR experiments showeda disordering effect of Menk on the lipid chains in all the bicelles except Bic/PG, whereas the study of the choline headgroupsindicated a decreased order of the lipids only in Bic/PE and Bic/PG. Our results suggest that the insertion depth of Menk intobicelles is modulated by their composition, more specifically by the balance between hydrophobic and electrostatic interactions.Menk would be buried at the lipid polar/apolar interface, the depth of penetration into the hydrophobic membrane core followingthe scaling Bic[Bic/PE[Bic/PS at the slightly acidic pH used in this study. The peptide would not insert into the bilayer coreof Bic/PG and would rather remain at the surface.Biophysical Journal Volume 85 July 2003 328–339Isabelle Marcotte,* Erick J. Dufourc,y Marise Ouellet,* and Miche`le Auger**De partement de Chimie, Centre de Recherche en Sciences et Inge nierie des Macromole cules, Universite´ Laval, Que´bec, Que bec,Canada, G1K 7P4; and yInstitut Europe en de Chimie et Biologie, FRE CNRS 2247, 33607 Pessac, Francehttp://www.biophysj.org/cgi/content/full/85/1/328
    Probing site-specific conformational distributions in protein folding with solid-state NMR
    We demonstrate an experimental approach to structural studies ofunfolded and partially folded proteins in which conformationaldistributions are probed at a site-specific level by 2D solid-state 13CNMR spectroscopy of glassy frozen solutions. Experiments onchemical denaturation of the 35-residue villin headpiece subdomain,a model three-helix-bundle protein with a known foldedstructure, reveal that 13C-labeled residues in the three helicalsegments of the folded state have markedly different conformationaldistributions in the unfolded state. Moreover, the 2D solidstateNMR line shapes near the unfolding midpoint do not fit asimple two-state model, in which the conformational distributionsof the unfolded component are assumed to be independent ofdenaturant concentration. Comparison with solid-state NMR spectraof peptides containing the individual helical segments suggestsan alternative two-step description of conformational distributionsin partially folded states of the helical villin headpiecesubdomain, in which chemical denaturation is viewed as a disruptionof tertiary contacts followed by equilibration of local secondarystructure according to the intrinsic helical propensities ofindividual segments.PNAS; 2005;102(9) 3284–3289Robert H. Havlin and Robert Tycko*Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520Edited by Peter G. Wolynes, University of California at San Diego, La Jolla, CA, and approved January 16, 2005 (received for review August 19, 2004)http://www.pnas.org/cgi/content/full/102/9/3284
    Backbone Conformational Constraints in a Microcrystalline U-15N-Labeled Protein by 3D Dipolar-Shift Solid-State NMR Spectroscopy
    Structural studies of uniformly labeled proteins by magic-angle spinning NMR spectroscopy have rapidly matured in recent years. Site-specific chemical shifts of several proteins have been assigned and structures determined from 2D or 3D data sets containing internuclear distance information. Here we demonstrate the application of a complementary technique for constraining protein backbone geometry using a site-resolved 3D dipolar-shift pulse sequence. The dipolar line shapes report on the relative orientations of 1H-15N[i] to 1H-15N[i+1] dipole vectors, constraining the torsion angles [i] and [i]. In addition, from the same 3D data set, several 1H-15N[i] to1H-15N[i+2] line shapes are extracted to constrain the torsion angles [i], [i], [i+1], and [i+1]. We report results for the majority of sites in the 56-residue 1 immunoglobulin binding domain of protein G (GB1), using 3D experiments at 600 MHz 1H frequency. Excellent agreement between the SSNMR results and a new 1.14 Å crystal structure illustrate the general potential of this technique for high-resolution structural refinement of solid proteins. J. Am. Chem. Soc., 128 (10), 3154 -3155, 2006. W. Trent Franks, Benjamin J. Wylie, Sara A. Stellfox, and Chad M. Rienstra*Department of Chemistry, Department of Biochemistry, and Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801 http://pubs.acs.org/cgi-bin/abstract.cgi/jacsat/2006/128/i10/abs/ja058292x.html
    Motional Heterogeneity in Poly(ether-block-amide) Copolymers As Revealed by Solid-State NMR
    An insight into the motional heterogeneity of a series of poly(ether-block-amide) copolymers is presented and discussed in terms of its NMR fingerprints dependent on a content and length of hard and soft segments and a microphase-separated morphology. Local-field dipolar spectra carry a straightforward signature of microphase-separated morphology endowed with a strong mobility gradient. The dipolar features of the poly(tetramethylene glycol) (PTMG) and polyamide-12 (PA) components, besides visualizing the presence of separated PTMG and PA phases, also give evidence for the presence of the dynamic heterogeneity of each component. 1H MAS spectra provide an another fingerprint of phase-separated systems. Although such spectra roughly show increasing line broadening at higher PA/PTMG ratio, they are mainly sensitive to the presence of the most mobile fragments and may give a distorted vision of intrinsic mobility of the soft component in the presence of its dynamic heterogeneity. 13C spectra bearing proton-carbon J-coupling features appear to be more sensitive to the length of the soft blocks and seem to bring a proper visualization of their overall mobility. Special attention has been paid to characterize motional heterogeneity of the soft component by exploiting cross-polarization transfer efficiency combined with indirect T2(1H) relaxation measurements. The cross-polarization inversion experiments provide, from heteronuclear dipolar interaction perspective, a corroborating visualization of the extent of motional distribution of the PTMG component. The revealed fingerprints of the motional heterogeneity of the soft component and the ways exploited in this work for their retrieval might be helpful for a better assessment of its role in the mechanical properties of thermoplastic elastomers. Macromolecules, 38 (22), 9200 -9209, 2005. Catherine Hucher, René-Paul Eustache, François Beaume, and Piotr Tekely*ARKEMA, Centre d'Etude de Recherche et Développement, 27470 Serquigny, France, and Methodologie RMN UMR CNRS 7565, Université H. Poincaré, 54506 Vandoeuvre-lès-Nancy, France http://pubs.acs.org/cgi-bin/abstract.cgi/mamobx/2005/38/i22/abs/ma051625q.html
    Binding of Peptides with Basic and Aromatic Residues to Bilayer Membranes
    PHENYLALANINE IN THE MYRISTOYLATED ALANINE-RICH C KINASE SUBSTRATE EFFECTOR DOMAIN PENETRATES INTO THE HYDROPHOBIC CORE OF THE BILAYER J. Biol. Chem., Vol. 278, Issue 24, 21459-21466, June 13, 2003 Wenyi Zhang {ddagger}, Evan Crocker §, Stuart McLaughlin ¶ and Steven O. Smith {ddagger} ||From the {ddagger} Department of Biochemistry and Cell Biology, Center for Structural Biology, State University of New York, Stony Brook, New York 11794-5115, § Department of Physics and Astronomy, Center for Structural Biology, State University of New York, Stony Brook, New York 11794-5115, ¶ Department of Physiology and Biophysics, Center for Structural Biology, State University of New York, Stony Brook, New York 11794-5115 http://www.jbc.org/cgi/content/full/278/24/21459
    A 2D Solid-State NMR Experiment To Resolve Overlapping Aromatic Resonances of Thiophene-Based Nematogens
    In this study, we demonstrate the feasibility of resolving overlapping 13C chemical shift spectral lines of aromatic rings in a thiophene-based nematogen in the mesophase using a 2D PITANSEMA solid-state NMR method. This technique provided the information about chemical shift values as well as dipolar couplings that are used for determining the orientational order parameter. Large C-H dipolar coupling values measured for thiophene in contrast to phenyl rings suggest that the heterocyclic ring is not part of the molecular axis. Using the order parameter, we determined the orientation of C-H vectors of the thiophene ring. We believe that the 2D solid-state NMR can be extended to other types of liquid crystalline materials such as the banana-based mesogens for determining the orientational order and bent angle. J. Am. Chem. Soc., 127 (19), 6958 -6959, 2005. Tanneru Narasimhaswamy, Dong-Kuk Lee, Kazutoshi Yamamoto, Narayanasastri Somanathan, and Ayyalusamy Ramamoorthy*Biophysics Research Division and Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, and Polymer Laboratory, Central Leather Research Institute, Adyar, Chennai, 600 020, India http://pubs.acs.org/cgi-bin/abstract.cgi/jacsat/2005/127/i19/abs/ja051160j.html
    Tautomerism and 1H and 13C NMR assignment of methyl derivatives of 9-hydroxyphenalenone
    9-Hydroxyphenalenone is a planar multicyclic b-keto-enol that demonstrates C2V symmetry on the NMRtimescale. Off-axis substitution breaks the molecular symmetry and results in tautomers. 1H and 13CNMRassignments were made for 9-hydroxyphenalenone and three methyl derivatives, and the solution-phasetautomers were determined.Magn. Reson. Chem. 2005; 43: 1053–1056Brian Honeyman,1 Charles Spalding,1 Dell Jensen, Jr.1∗ and Robert C. Haddon21 Augustana College, Chemistry Department, 639 38th Street, Rock Island, IL 61201, USA2 University of California at Riverside, Departments of Chemistry and Chemical & Environmental Engineering, Pierce Hall Annex 203, Riverside, CA92521-0403, USA
    Amplitude-modulated decoupling in rotating solids: A bimodal Floquet approach
    This paper centers on a theoretical study of amplitude-modulated heteronuclear decoupling in solid-state NMR under magic-angle spinning (MAS). A spin system with a single isolated rare spin coupled to a large number of abundant spins is used in the analysis. The phase-alternating decoupling scheme (XiX decoupling) is analyzed using bimodal Floquet theory and the operator-based perturbation method developed by van Vleck. An effective Hamiltonian correct to second order is calculated for the spin system under XiX decoupling. The results of these calculations indicate that under XiX decoupling the main contribution to the residual line width comes from a cross-term between the heteronuclear and the homonuclear dipolar couplings. This is in contrast to continuous-wave decoupling, where the residual line width is dominated by the cross-term between the heteronuclear dipolar coupling and the chemical-shielding tensor of the irradiated spin. For high-power decoupling the method results in very good decoupling provided that certain unfavorable recoupling conditions, imposed by specific ratios of the amplitude modulation frequency and the MAS frequency, are avoided. For low-power decoupling, the method leads to acceptable decoupling when the pulse length corresponds to an integer multiple of a 2π rotation and the rf-field amplitude is less than a quarter of the MAS frequency. The performance of the XiX scheme is analyzed over a range of values of the rf power, and numerical results that agree well with the most recent experimental observations are presented.Solid State Nuclear Magnetic Resonance 29 (2006) 2–21 Matthias Ernsta, Corresponding Author Contact Information, E-mail The Corresponding Author, Helen Geenb and Beat H. MeieraaPhysical Chemistry, ETH Zürich, CH-8093 Zürich, SwitzerlandbSchool of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, UKhttp://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6THK-4H98T1P-1&_coverDate=02%2F28%2F2006&_alid=384675299&_rdoc=1&_fmt=&_orig=search&_qd=1&_cdi=5285&_sort=d&view=c&_acct=C000039280&_version=1&_urlVersion=0&_userid=699479&md5=df5385cf52bb835d61a135200a71fba1
    Solid state 19F NMR methods for studying biomembranes
    Progress in Nuclear Magnetic Resonance Spectroscopy 46 (2005) 1–21Anne S. Ulricha, b, Corresponding Author Contact Information, E-mail The Corresponding AuthoraUniversity of Karlsruhe, Institute of Organic Chemistry, Fritz-Haber-Weg 6, Karlsruhe 76131, GermanybInstitute for Instrumental Analysis, Forschungszentrum Karlsruhe, Germanyhttp://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6THC-4F3FS9Y-1&_user=699479&_handle=V-WA-A-W-Z-MsSAYVA-UUA-U-AAVZWEABVV-AAVBYDWAVV-DZBWAVWZV-Z-U&_fmt=full&_coverDate=03%2F17%2F2005&_rdoc=1&_orig=browse&_srch=%23toc%235279%232005%23999539998%23585683!&_cdi=5279&view=c&_acct=C000039280&_version=1&_urlVersion=0&_userid=699479&md5=c549ccaf8c50ad66f88702d21f49d6e8
    Characterization of Dynamics of Perdeuterated Proteins by MAS Solid-State NMR
    We show in this communication that dynamic information for uniformly 2H,13C,15N isotopically enriched, crystalline proteins can be obtained by MAS solid-state NMR spectroscopy. The experiments make use of the deuterium quadrupolar tensor, which is the dominant interaction mechanism. Dynamic properties are accessed by measurement of the size of the quadrupolar coupling constant, Cq, and the value of the asymmetry parameter, , via evolution of the deuterium chemical shift, as well as by measurement of deuterium T1 relaxation times. Three-dimensional experiments are performed in order to obtain site-specific resolution. Due to proton dilution, no proton decoupling is required in the carbon evolution periods at MAS rotation frequencies of 10 kHz.J. Am. Chem. Soc., 127 (32), 11208 -11209, 2005. 10.1021/ja051830l S0002-7863(05)01830-5 Maggy Hologne, Katja Faelber, Anne Diehl, and Bernd Reif*Forschungsinstitut für Molekulare Pharmakologie (FMP), Robert-Rössle-Str. 10, 13125 Berlin, Germanyreif@fmp-berlin.dehttp://pubs.acs.org/cgi-bin/abstract.cgi/jacsat/2005/127/i32/abs/ja051830l.html
    Solid-State NMR Studies of the Structure, Dynamics, and Assembly of -Sheet Membrane Peptides and -Helical Membrane Proteins with Antibiotic Activities
    Abstract:-Sheet antimicrobial peptides and -helical channel-forming colicins are bactericidal molecules that target the lipid membranes of sensitive cells. Understanding the mechanisms of action of these proteins requires knowledge of their three-dimensional structure in the lipid bilayer. Solid-state NMR has been used to determine the conformation, orientation, depth of insertion, oligomerization, mobility, and lipid interaction of these membrane peptides and proteins. We review the NMR methods developed and applied to study the structure and dynamics of these antibiotic membrane proteins. These studies shed light on how these peptides disrupt lipid membranes and provide fundamental insights into the folding of -sheet and -helical membrane proteins. Mei Hong Department of Chemistry, Iowa State University, Ames, Iowa 50011http://pubs.acs.org/cgi-bin/abstract.cgi/achre4/asap/abs/ar040037e.html
    Ion Solvation by Channel Carbonyls Characterized by 17O Solid-State NMR at 21 T
    Abstract:Recently available ultrahigh magnetic fields offer new opportunities for studies of quadrupole nuclei in biological solids because of the dramatic enhancement in sensitivity and resolution associated with the reduction of second-order quadrupole interactions. Here, we present a new approach for understanding the function and energetics of ion solvation in channels using solid-state 17O NMR spectroscopy of single-site 17O-labeled gramicidin A. The chemical shift and quadrupole coupling parameters obtained in powder samples of lyophilized material are similar to those shown in the literature for carbonyl oxygens. In lipid bilayers, it is found that the carbonyl 17O anisotropic chemical shift of Leu10, one of the three carbonyl oxygens contributing to the ion binding site in gramicidin A, is altered by 40 ppm when K+ ion binds to the channel, demonstrating a high sensitivity to such interactions. Moreover, considering the large breadth of the carbonyl 17O chemical shift (>500 ppm), the recording of anisotropic 17O chemical shifts in bilayers aligned with respect to magnetic field B0 offers high-quality structural restraints similar to 15N and 13C anisotropic chemical shifts. Jun Hu, Eduard Y. Chekmenev, Zhehong Gan, Peter L. Gor'kov, Saikat Saha, William W. Brey, and Timothy A. Cross* Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, Institute of Molecular Biophysics, Florida State University, Tallahassee, Florida 32306, and National High Magnetic Field Laboratory, Tallahassee, Florida 32310 http://pubs.acs.org/cgi-bin/abstract.cgi/jacsat/2005/127/i34/abs/ja0535413.html
    Magic Angle Spinning Solid-State NMR Spectroscopy for Structural Studies of Protein Interfaces. Resonance Assignments of Differentially Enriched Escherichia coli Thioredoxin Reassembled by Fragment Complementation
    De novo site-specific backbone and side-chain resonance assignments are presented for U-15N-(1-73)/U-13C,15N(74-108) reassembly of Escherichia coli thioredoxin by fragment complementation,determined using solid-state magic angle spinning NMR spectroscopy at 17.6 T. Backbone dihedral anglesand secondary structure predicted from the statistical analysis of 13C and 15N chemical shifts are in generalagreement with solution values for the intact full-length thioredoxin, confirming that the secondary structureis retained in the reassembled complex prepared as a poly(ethylene glycol) precipitate. The differentiallabeling of complementary thioredoxin fragments introduced in this work is expected to be beneficial forhigh-resolution structural studies of protein interfaces formed by protein assemblies by solid-state NMRspectroscopy.Dabeiba Marulanda,† Maria Luisa Tasayco,*,‡ Ann McDermott,§ Marcela Cataldi,‡Vilma Arriaran,‡ and Tatyana Polenova*,†Contribution from the Department of Chemistry and Biochemistry, Brown Laboratories,UniVersity of Delaware, Newark, Delaware 19716, Department of Chemistry, Science Building,City College of the City UniVersity of New York, New York, New York 10031, andDepartment of Chemistry, HaVemeyer Hall, Columbia UniVersity, New York, New York 10027http://pubs.acs.org/cgi-bin/abstract.cgi/jacsat/2004/126/i50/abs/ja0464589.html
    Observation of Ligand Binding to Cytochrome P450 BM-3 by Means of Solid-State NMR Spectroscopy
    Abstract:A broad understanding of the binding modes of ligands and inhibitors to cytochrome P450 isvital for the development of new drugs. We investigated ligand binding in a site-specific fashion oncytochrome P450 BM-3 from Bacillus megaterium, a 119 kDa paramagnetic enzyme, using solid-statemagic angle spinning nuclear magnetic resonance methods. Selective labeling and longitudinal relaxationeffects were utilized to identify the peaks in a site-specific fashion and to provide evidence for binding.Well-resolved one-dimensional and two-dimensional NMR spectra of cytochrome P450 BM-3 reveal shiftsupon binding of its substrate, N-palmitoylglycine. These data are consistent with the crystallographic resultthat a biochemically important amino acid residue, Phe87, moves upon ligation. This experimental schemeprovides a tool for probing ligand binding for complex systems.Tijana Jovanovic and Ann E. McDermott* Contribution from the Department of Chemistry, Columbia UniVersity, 3000 Broadway,New York, New York 10027J. AM. CHEM. SOC. 2005, 127, 13816-13821http://pubs.acs.org/cgi-bin/article.cgi/jacsat/2005/127/i40/pdf/ja0438314.pdf
    NMR studies of structure and dynamics in fruit cuticle polyesters.
    Stark RE, Yan B, Ray AK, Chen Z, Fang X, Garbow JR. NMR studies of structure and dynamics in fruit cuticle polyesters. Solid State Nucl Magn Reson. 2000 May, 16(1-2):37-45.
    Magnetic Resonance in Chemistry, special issue, Solid-state NMR on biological systems.
    http://www3.interscience.wiley.com/cgi-bin/jissue/106600861
    Unlocking the Molecular Structure of Fungal Melanin Using 13C Biosynthetic Labeling and Solid-State NMR.
    Unlocking the Molecular Structure of Fungal Melanin Using 13C Biosynthetic Labeling and Solid-State NMRShiying Tian, Javier Garcia-Rivera, Bin Yan, Arturo Casadevall, and Ruth E. StarkBiochemistry; 2003; 42(27) pp 8105 - 8109; (Accelerated Publication) DOI: 10.1021/bi0341859


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