Carr−Purcell−Meiboom−Gill relaxation dispersion NMR spectroscopy has evolved into a powerful approach for the study of low populated, invisible conformations of biological molecules. One of the powerful features of the experiment is that chemical shift differences between the exchanging conformers can be obtained, providing structural information about invisible excited states. Through the development of new labeling approaches and NMR experiments it is now possible to measure backbone 13Cα and 13CO relaxation dispersion profiles in proteins without complications from 13C−13C couplings. Such measurements are presented here, along with those that probe exchange using 15N and 1HN nuclei. A key experimental design has been the choice of an exchanging system where excited-state chemical shifts were known from independent measurement. Thus it is possible to evaluate quantitatively the accuracy of chemical shift differences obtained in dispersion experiments and to establish that in general ...
Allosteric transmission of information between distant sites in biological macromolecules often involves collective transitions between active and inactive conformations. Nuclear magnetic resonance (NMR) spectroscopy can yield detailed information on these dynamics. In particular, relaxation dispersion techniques provide structural, dynamic, and mechanistic information on conformational transitions occurring on the millisecond to microsecond timescales. In this review, we provide an overview of the theory and analysis of Carr-Purcell-Meiboom-Gill (CPMG) relaxation dispersion NMR experiments and briefly describe their application to the study of allosteric dynamics in the homeodomain from the PBX transcription factor (PBX-HD). CPMG NMR data show that local folding (helix/coil) transitions in one part of PBX-HD help to communicate information between two distant binding sites. Furthermore, the combination of CPMG and other spin relaxation data show that this region can also undergo local ...
Structural plasticity and Mg2+ binding properties of RNase P P4 from combined analysis of NMR residual dipolar couplings and motionally decoupled spin relaxation.
Comparative studies on manual and automatic backbone chemical shift assignments of 2H-13C-15N-labeled Ube2g1. . Biblioteca virtual para leer y descargar libros, documentos, trabajos y tesis universitarias en PDF. Material universiario, documentación y tareas realizadas por universitarios en nuestra biblioteca. Para descargar gratis y para leer online.
The model-free analysis of NMR relaxation data, which is widely used for the study of protein dynamics, consists of the separation of the Brownian rotational diffusion from internal motions relative to the diffusion frame and the description of these internal motions by amplitude and timescale. Through parametric restriction and the addition of the Rex parameter a number of model-free models can be constructed. The model-free problem is often solved by initially estimating the diffusion tensor. The model-free models are then optimised and the best model is selected. Finally, the global model of all diffusion and model-free parameters is optimised. These steps are repeated until convergence. This thesis will investigate all aspects of the model-free data analysis chain. (For complete abstract open document ...
The European Physical Journal D (EPJ D) presents new and original research results in Atomic, Molecular, Optical and Plasma Physics
Author: Andronesi, O. et al.; Genre: Journal Article; Published in Print: 2005-09-21; Title: Determination of membrane protein structure and dynamics by magic-angle-spinning solid-state NMR spectroscopy
Author: Andronesi, O. et al.; Genre: Journal Article; Published in Print: 2005-09-21; Title: Determination of membrane protein structure and dynamics by magic-angle-spinning solid-state NMR spectroscopy
Abstract : MC1 is the most abundant architectural protein present in Methanosarcina thermophila CHTI55 in laboratory growth conditions and is structurally unrelated to other DNA-binding proteins. MC1 functions are to shape and to protect DNA against thermal denaturation by binding to it. Therefore, MC1 has a strong affinity for any double-stranded DNA. However, it recognizes and preferentially binds to bent DNA, such as four-way junctions and negatively supercoiled DNA minicircles. Combining NMR data, electron microscopy data, biochemistry, molecular modelisation and docking approaches, we proposed recently a new type of DNA/protein complex, in which the monomeric protein MC1 binds on the concave side of a strongly bent 15 base pairs DNA. We present here the NMR chemical shifts assignments of each partner in the complex, 1H 15N MC1 protein and 1H 13C 15N bent duplex DNA, as first step towards the first experimental 3D structure of this new type of DNA/protein complex.. ...
TY - JOUR. T1 - Chemical shift assignments of the C-terminal Eps15 homology domain-3 EH domain. AU - Spagnol, Gaelle. AU - Reiling, Calliste. AU - Kieken, Fabien. AU - Caplan, Steve. AU - Sorgen, Paul L.. PY - 2014/10/1. Y1 - 2014/10/1. N2 - The C-terminal Eps15 homology (EH) domain 3 (EHD3) belongs to a eukaryotic family of endocytic regulatory proteins and is involved in the recycling of various receptors from the early endosome to the endocytic recycling compartment or in retrograde transport from the endosomes to the Golgi. EH domains are highly conserved in the EHD family and function as protein-protein interaction units that bind to Asn-Pro-Phe (NPF) motif-containing proteins. The EH domain of EHD1 was the first C-terminal EH domain from the EHD family to be solved by NMR. The differences observed between this domain and proteins with N-terminal EH domains helped describe a mechanism for the differential binding of NPF-containing proteins. Here, structural studies were expanded to include ...
For a quarter of a century X-ray diffraction in single crystals was unique in its ability to solve three-dimensional structures of proteins and nucleic acids at atomic resolution. The situation changed in 1984 with the completion of a protein structure determination by nuclear magnetic resonance (NMR) spectroscopy in solution, and today NMR is a second widely used method for biomacromolecular structure determination. This review describes the method of NMR structure determination of biological macromolecules, and attempts to place NMR structure determination in perspective with X-ray crystallography. NMR is most powerful for studies of relatively small systems with molecular weights up to about 30000, but these structures can be obtained in near-physiological milieus. The two techniques have widely different time scales which afford different insights into internal molecular mobility as well as different views of protein or nucleic acid molecular surfaces and hydration. Generally, in addition to ...
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Hsp90 is one of the most abundant chaperone proteins in the cytosol. In an ATP-dependent manner it plays an essential role in the folding and activation of a range of client proteins involved in signal transduction and cell cycle regulation. We used NMR shift perturbation experiments to obtain infor …
As a member of the wwPDB, the RCSB PDB curates and annotates PDB data according to agreed upon standards. The RCSB PDB also provides a variety of tools and resources. Users can perform simple and advanced searches based on annotations relating to sequence, structure and function. These molecules are visualized, downloaded, and analyzed by users who range from students to specialized scientists.
1BT7: THE SOLUTION NMR STRUCTURE OF THE N-TERMINAL PROTEASE DOMAIN OF THE HEPATITIS C VIRUS (HCV) NS3-PROTEIN, FROM BK STRAIN, 20 STRUCTURES
Dr David Pugh (Deputy Programme Co-ordinator, UWC) has a background in Applied Mathematics and Physics, and has experience of determining protein structures using nuclear magnetic resonance (NMR) spectroscopy. Dr Pugh is the leader of the Structural Biology Group at UWC. He will also co-ordinate the NMR component of the Masters Programme in Structural Biology, as well as contribute lectures on mathematical techniques and NMR spectroscopy.. ...
The presence of slow motions with large amplitudes, as detected by measurements based on residual dipolar couplings [Peti, W., Meiler, J., Brueschweiler, R. and Griesinger, C. (2002) J. Am. Chem. Soc.
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A 3-year postdoctoral position in Membrane Protein Structure / Protein NMR is available at the University of Warwick, UK under the supervision of Dr. Ann Dixon.. The post is funded by the Medical Research Council, and is focused on exploring the roles of transmembrane domains in the assembly and function of the B-cell receptor (BCR), one of the most important immune receptors in humans which controls B-cell development, activity, selection and death. Aberrant BCR signalling leads to autoimmune diseases, B-cell leukaemias, and lymphomas, thus it is a therapeutic target of great interest. The project involves use of a variety of biochemical and biophysical methods (especially solution-state NMR spectroscopy) to investigate the structures and interactions of the BCR transmembrane domains in model membranes and in natural membranes. We will work in close collaboration with experts in the biology of this receptor, in order to translate our structural findings in situ into cells and more fully relate ...
Average backbone N and HN chemical shift perturbation in Aβ42 upon addition of IAPP-GI.The values are reported as slope of the best fitted line to chemical shi
TY - CHAP. T1 - In-Cell Protein NMR Spectroscopy. AU - Burz, David S.. AU - Cowburn, David. AU - Dutta, Kaushik. AU - Shekhtman, Alexander. PY - 2012/3/21. Y1 - 2012/3/21. N2 - Structural biology in general, including NMR, is highly reductionist-simplifying complex systems to their component parts, and extrapolating to the native interactions that occur in cells and tissues. The strengths of NMR analysis-high-resolution structure determination, intermolecular interface identification, dynamic molecular descriptions, site-specific electronic characterization-are patently applicable to cells and tissues, but face a number of technical complexities, including sensitivity, selectivity, and localization. Additionally, while there is adequate understanding of crowding and similar physicochemical effects in homogeneous polymer systems, the heterogeneity of the cellular environment adds an additional challenge (or opportunity) for potentially new phenomena to be observed. Current literature describes a ...
The linear analysis of chemical shifts (LACS) has provided a robust method for identifying and correcting 13C chemical shift referencing problems in data from protein NMR spectroscopy. Unlike other ap
For the Ras-binding domain of the protein kinase Byr2, only a limited number of NOE contacts could be initially assigned unambiguously, as the quality of the NOESY spectra was too poor. However, the use of residual (1)H-(15)N dipolar couplings in the beginning of the structure determination process allows to overcome this problem. We used a three-step recipe for this procedure. A previously unknown structure could be calculated reasonably well with only a limited number of unambiguously assigned NOE contacts. ...
Authors: Samson, Camille; Herrada, Isaline; Celli, Florian; Theillet, Francois-Xavier; Zinn-Justin, Sophie. Citation: Samson, Camille; Herrada, Isaline; Celli, Florian; Theillet, Francois-Xavier; Zinn-Justin, Sophie. 1H, 13C and 15N backbone resonance assignment of the intrinsically disordered region of the nuclear envelope protein emerin Biomol. NMR Assign. 10, 179-182 (2016).. Assembly members: ...
Many important biological processes occur near or in membranes. The role of membranes is not merely confined to compartmentalization, they also form the matrix for membrane associated proteins and are of functional importance. Membrane associated proteins on the other hand require specific membrane properties for proper function. The interactions between membranes and proteins are thus of paramount importance and are at the focus of this work.. To draw valid conclusions about the nature of such interactions the membrane mimetics required in biophysical methods must faithfully mimic crucial properties of biological membranes. To this end, new types of small isotropic bicelles which mimic plant and bacterial membranes were characterized by their size and lipid dynamics using solution-state NMR. Small isotropic bicelles are specifically well suited for solution-state NMR studies since they maintain a bilayer while being sufficiently small to conduct interpretable experiments at the same time. ...
Using the advanced search option: there are 227 solution NMR structures of proteins with more than 200 residues. Thus, 2% of the 10,282 solution NMR structures are of protein with more than 200 residues. Furthermore, 0.3% of the 70,795 structures if proteins with more than 200 residues are determined by solution NMR ...
Postdoctoral position in solid- and solution-state NMR of membrane proteins at College of Staten Island (CSI) - City University of New York, New York, USA. A postdoctoral position is available at CSI-CUNY in Prof. Ming Tangs lab starting in January 2016. The project is to investigate the function-modulating interactions between proteins and membrane components by solving structures of membrane-associated protein complexes and aggregates. CSI NMR facility has a 600MHz solution instrument with cryoprobe, and the personnel also have access to the wide range of solution and solid spectrometers at the New York Structural Biology Center. The candidate is expected to have strong skills with recombinant expression of isotopically labeled proteins, and is familiar with solution NMR techniques for protein structure determination. Knowledge of solid-state NMR techniques is optional. Minority and female candidates are encouraged to apply. Please send applications with a CV and names of three references to ...
CYANA v2.1, T Herrmann, P Guntert and K Wuthrich - automated peak assignments, refinement, structure solution. NMRPipe, F Delaglio, S Grzesiek, GW Vuister, G Zhu, J Pfeifer and A Bax - processing. SPARKY v3, T Goddard - chemical shift assignment, data analysis. VNMR, Varian - collection. TALOS, G Cornilescu, F Delaglio and A Bax - coupling constant ...
CYANA v2.1, Guntert, Mumenthaler and Wuthrich - structure solution. AutoAssign v2.4.0, Zimmerman, Moseley, Kulikowski and Montelione - chemical shift assignment. NMRPipe, Delaglio, Grzesiek, Vuister, Zhu, Pfeifer and Bax - processing. TOPSPIN v2.1, Bruker Biospin - collection. SPARKY v3.113, Goddard - data analysis. TALOS, Cornilescu, Delaglio and Bax - geometry optimization. CNS v1.1, Brunger, Adams, Clore, Gros, Nilges and Read - refinement. RPF(AutoStructure) v2.2.1, Huang, Tejero, Powers and Montelione - validation. Molmol, Koradi, Billeter and Wuthrich - visualization. PSVS, Bhattacharya and Montelione - validation. PDBStat v5.0, Tejero R.; Montelione GT - validation. MolProbity, Richardson - validation. Procheck, Laskowski, MacArthur, Smith, Jones, Hutchinson, Morris, Moss and Tho - validation ...
Nuclear Magnetic Resonance Structure of an 8 x 8 Nucleotide RNA Internal Loop Flanked on Each Side by Three Watson-Crick Pairs and Comparison to Three-Dimensional Predictions ...
Heres a neat paper thats shown up on arXiv.org on protein structures. The authors, from Yale and Edinburgh, are specifically comparing X-ray crystallographic
Abou Samra, A., A. Robert, C. Gov, L. Favre, L. Eloy, E. Jacquet, J. Bignon, J. Wiels, S. Desrat and F. Roussi (2018). Dual inhibitors of the pro-survival proteins Bcl-2 and Mcl-1 derived from natural compound meiogynin A. Eur J Med Chem 148: 26-38.. Andre, E., V. Derrien, P. Sebban, N. Assrir, E. Lescop and S. Bernad (2018). Impact of A90P, F106L and H64V mutations on neuroglobin stability and ligand binding kinetics. J Biol Inorg Chem.. Casiraghi, M., M. Damian, E. Lescop, J. L. Baneres and L. J. Catoire (2018). Illuminating the Energy Landscape of GPCRs: The Key Contribution of Solution-State NMR Associated with Escherichia coli as an Expression Host. Biochemistry 57(16): 2297-2307.. Cavailles, M., A. Bornet, X. Jaurand, B. Vuichoud, D. Baudouin, M. Baudin, L. Veyre, G. Bodenhausen, J. N. Dumez, S. Jannin, C. Coperet and C. Thieuleux (2018). Tailored Microstructured Hyperpolarizing Matrices for Optimal Magnetic Resonance Imaging. Angew Chem Int Ed Engl 57(25): 7453-7457.. Concilio, M. ...
Saturation transfer difference NMR spectroscopy was employed to characterize epitopes of macrolide antibiotics, azithromycin, oleandomycin and telithromycin binding to bovine serum albumin. The structural parts of azithromycin and...
TY - JOUR. T1 - Changes in calmodulin main-chain dynamics upon ligand binding revealed by cross-correlated NMR relaxation measurements. AU - Wang, Tianzhi. AU - Frederick, Kendra King. AU - Igumenova, Tatyana I.. AU - Wand, A. Joshua. AU - Zuiderweg, Erik R P. PY - 2005/1/26. Y1 - 2005/1/26. N2 - The fast dynamics of protein backbones are often investigated by nuclear magnetic relaxation experiments that report on the degree of spatial restriction of the amide bond vector. By comparing calmodulin in the peptide-bound and peptide-free states with these classical methods, we observe little difference in the dynamics of the polypeptide main chain (average order parameter decrease of 0.01 unit upon binding). However, when using NMR methods that monitor the mobility of the CO-Cα bond vector, we reveal a significant reduction of dynamics of the protein main chain (average order parameter decrease of 0.048 units). Previous investigations have suggested that the side-chain dynamics is reduced by an ...
Li, Yan, Zhong, Wenhe, Koay, Ann Zhufang, Ng, Hui Qi, Nah, Qianhui et al. 2019. Backbone resonance assignment for the full length tRNA-(N1G37) methyltransferase of Pseudomonas aeruginosa. Biomolecular NMR Assignments, 13 (2 ...
Backbone resonance assignment is a critical first step in the investigation of proteins by NMR. This is traditionally achieved with a standard set of experiments, most of which are not optimal for large proteins. Of these, HNCA is the most sensitive experiment that provides sequential correlations. …
TY - CHAP. T1 - The hybrid solution/solid-state NMR method for membrane protein structure determination. AU - Veglia, G.. AU - Traaseth, N. J.. AU - Shi, L.. AU - Verardi, R.. AU - Gopinath, T.. AU - Gustavsson, M.. PY - 2012. Y1 - 2012. N2 - This chapter describes a hybrid nuclear magnetic resonance (NMR) method for the structure determination of membrane proteins. The method consists in combining distance and orientational restraints derived from both solution and solid-state NMR techniques into a hybrid energy function that is minimized using simulated annealing calculations. Using this approach, we are able to determine the structural ensemble, topological orientation, and depth of insertion of membrane proteins in lipid environments. The feasibility of this method is demonstrated for three different single-pass membrane proteins ranging from 3 to 30. kDa in molecular weight. Finally, this chapter provides an overview of the most recent NMR pulse sequences with enhanced sensitivity and ...
Abstract: Using 13C solid-state nuclear magnetic resonance(NMR) we studied the structures of two spidroin-like polymers which were synthesized by the polymerization of polyalanine ((Ala)5) with oligomers of polystyrene(PS, MW=2000) and polyisoprene(PI, MW=2210). 13C CP/MAS (cross polarization/magic angle spinning) NMR spectra and spin-lattice relaxation time in the rotating frame (T1ρ(13C)) results of the polymers indicated that the chemical shifts of (Ala)5 in both polymers of polystyrene-co-polyalanine (PS-co-PAL) and polyisoprene-co-polyalanine (PI-co-PAL) were almost the same. This means that (Ala)5 peptide segments in the two polymers have similar chemical environments and secondary structures. The similar T1ρ(13C) values for (Ala)5 in the two polymers indicate that (Ala)5 peptide segments also have similar aggregate structures. The mechanical properties of the two spidroin-like polymers are quite different: PS-co-PAL is granular and tough while PI-co-PAL is rubber-like and tensible at ...
The magic angle is a precisely defined angle, the value of which is approximately 54.7356°. The magic angle is a root of a second-order Legendre polynomial, P2(cos θ) = 0, and so any interaction which depends on this second-order Legendre polynomial vanishes at the magic angle. This property makes the magic angle of particular importance in magic angle spinning solid-state NMR spectroscopy. In magnetic resonance imaging, structures with ordered collagen, such as tendons and ligaments, oriented at the magic angle may appear hyperintense in some sequences, this is called the magic angle artifact or effect. The magic angle θm is θ m = arccos ⁡ 1 3 = arctan ⁡ 2 ≈ 0.955 32 rad ≈ 54.7 ∘ , {\displaystyle \theta _{\mathrm {m} }=\arccos {\frac {1}{\sqrt {3}}}=\arctan {\sqrt {2}}\approx 0.955\,32\ {\text{rad}}\approx 54.7^{\circ }\!,} where arccos and arctan are the inverse cosine and tangent functions respectively. A195696 θm is the angle between the space diagonal of a cube and any of its ...
Abstract: Biological assemblies with specific function or pathogenicity are widespread within organisms; however, their insolubility, amorphous properties, and large size are the major obstacles for structure determination via solution NMR spectroscopy and X-ray crystallography. In contrast, solid-state NMR (ssNMR) spectroscopy is not limited by the solubility or crystallinity of the sample and is a potent method to determine the structure of protein assemblies at atomic resolution. High magnetic field, fast magic-angle spinning (MAS), isotope labeling schemes, and improved methodology in ssNMR have enabled resonance assignment and restraints in structure determination among protein assemblies. This review first discusses methods of obtaining structural restraints by ssNMR. Optimization of sample preparation is an effective approach to increase homogeneity in the conformation, thus also improving the resolution of ssNMR spectra. Furthermore, the resolution of 13C spectra can be further improved ...
The surface chemistry of self-assembled hydrogel fibres - their charge, hydrophobicity and ion-binding dynamics - is recognised to play an important role in determining how the gels develop as well as their suitability for different applications. However, to date there are no established methodologies for the study of this surface chemistry. Here, we demonstrate how solution-state NMR spectroscopy can be employed to measure the surface chemical properties of the fibres in a range of hydrogels formed from N-functionalised dipeptides, an effective and versatile class of gelator that has attracted much attention. By studying the interactions with the gel fibres of a diverse range of probe molecules and ions, we can simultaneously study a number of surface chemical properties of the NMR invisible fibres in an essentially non-invasive manner. Our results yield fresh insights into the materials. Most notably, gel fibres assembled using different tiggering methods bear differing amounts of negative ...
Establishing connectivity and proximity of nuclei is an important step in elucidating the structure and dynamics of molecules in solids using magic angle spinning (MAS) NMR spectroscopy. Although recent studies have successfully demonstrated the feasibility of proton-detected multidimensional solid-state NMR experiments under ultrafast-MAS frequencies and obtaining high-resolution spectral lines of protons, assignment of proton resonances is a major challenge. In this study, we first re-visit and demonstrate the feasibility of 2D constant-time uniform-sign cross-peak correlation (CTUC-COSY) NMR experiment on rigid solids under ultrafast-MAS conditions, where the sensitivity of the experiment is enhanced by the reduced spin-spin relaxation rate and the use of low radio-frequency power for heteronuclear decoupling during the evolution intervals of the pulse sequence. In addition, we experimentally demonstrate the performance of a proton-detected pulse sequence to obtain a 3D {sup 1}H/{sup ...
Solid-state NMR spectroscopy can provide site-resolved information about protein dynamics over many time scales. Here we combine protein deuteration, fast magic-angle spinning (~45-60kHz) and proton detection to study dynamics of ubiquitin in microcrystals, and in particular a mutant in a region that undergoes microsecond motions in a β-turn region in the wild-type protein. We use (15)N R1ρ relaxation measurements as a function of the radio-frequency (RF) field strength, i.e. relaxation dispersion, to probe how the G53A mutation alters these dynamics. We report a population-inversion of conformational states: the conformation that in the wild-type protein is populated only sparsely becomes the predominant state. We furthermore explore the potential to use amide-(1)H R1ρ relaxation to obtain insight into dynamics. We show that while quantitative interpretation of (1)H relaxation remains beyond reach under the experimental conditions, due to coherent contributions to decay, one may extract qualitative
In this thesis solid state NMR experiments on a variety of minerals and glasses are described with the aim of studying the dependence of their structure on the chemical composition. Chapter 1 introduces the reader to the subject. Chapter 2 describes 23Na and 27Al NMR experiments on a number of alkali fluoroaluminates. These substances ... read more consist of AIF6 octahedra which can be linked together to form a variety of structures, similar to the way in which Si04 and AI04 tetrahedra are linked together in aluminosilicates. The 23Na and 27Al chemical shifts correlate well with the type of structure. AIF3 is a network structure and has the most negative 27Al chemical shift (-16 ppm). The chemical shift increases from -3 and -1 ppm in the sheet structure chiolite (NasAI3F14) to 0 ppm in cryolite (N~AIF6) The 23Na chemical shift is dependent of the number of fluorines coordinating Na: Na in an NaF6 group has a more positive chemical shift than Na in NaFs. Additionally, 27Al chemical shifts for ...
We report a solid-state 17O NMR study of the 17O electric-field-gradient (EFG) and chemical shielding (CS) tensors for the carboxyl oxygen in an l-alanine hydrochloride. Using [17O]- and [13C,17O]-l-alanine hydrochlorides, both the magnitudes and the orientations in the molecular frame of the 17O EFG and CS tensors could be determined by the analysis of the 17O magic-angle spinning (MAS) and stationary NMR spectra. For the carbonyl oxygen, the smallest EFG tensor component, VXX, and the largest EFG component, VZZ, roughly lies in the carboxyl molecular plane and the direction of VXX is parallel to the dipolar vector between 13C and 17O, that is, the direction of CO bond. The angles between the intermediate EFG component, VYY, and δ33 component, and between δ22 component and VZZ are found to be approximately 10° and 35°, respectively. We also present the results of the quantum chemical calculations for a theoretical hydrogen-bonding model, indicating that hydrogen-bonding strengths make it ...
Solution NMR structure of Lin0431 protein from Listeria innocua reveals high structural similarity with domain II of bacterial transcription antitermination protein NusG ...
Abstract: Transition-metal dithiolene complexes have interesting structures and fascinating redox properties, making them promising candidates for a number of applications, including superconductors, photonic devices, chemical sensors, and catalysts. However, not enough is known about the molecular electronic origins of these properties. Multinuclear solid-state NMR spectroscopy and first-principles calculations are used to examine the molecular and electronic structures of the redox series [Pt(tfd)2]z- (tfd = S2C2(CF3)2; z = 0, 1, 2; the anionic species have [NEt4]+ countercations). Single-crystal X-ray structures for the neutral (z = 0) and the fully reduced forms (z = 2) were obtained. The two species have very similar structures but differ slightly in their intraligand bond lengths. 19F−195Pt CP/CPMG and 195Pt magic-angle spinning (MAS) NMR experiments are used to probe the diamagnetic (z = 0, 2) species, revealing large platinum chemical shielding anisotropies (CSA) with distinct CS ...
This volume reviews the brief history of NMR chemical shielding and presents snap shots of the developing field, including: new methodologies to calculate NMR chemical shifts, calculation of chemical shifts in molecular systems of biological interest, advances in the undestanding of chemical shifts, and the modelling of chemical shifts in inorganic compounds.
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Anet, F. A. L. and Bourn, A. J. R.: Nuclear magnetic resonance spectral assignments from nuclear Overhauser effects, J. Am. Chem. Soc., 87, 5250-5251, https://doi.org/10.1021/ja00950a048, 1965. Arnold, L., Marx, A., Thiele, C. M., and Reggelin, M.: Polyguanidines as chiral orienting media for organic compounds, Chem.-Eur. J., 16, 10342-10346, https://doi.org/10.1002/chem.201000940, 2010. Bax, A.: Weak alignment offers new NMR opportunities to study protein structure and dynamics, Protein Sci., 12, 1-16, https://doi.org/10.1110/ps.0233303, 2003. Berger, R., Courtieu, J., Gil, R. R., Griesinger, C., Köck, M., Lesot, P., Luy, B., Merlet, D., Navarro-Vázquez, A., Reggelin, M., Reinscheid, U. M., Thiele, C. M., and Zweckstetter, M.: Is enantiomer assignment possible by NMR spectroscopy using residual dipolar couplings from chiral nonracemic alignment media? - A critical assessment, Angew. Chem. Int. Edit., 51, 8388-8391, https://doi.org/10.1002/anie.201107626, 2012. Bifulco, G., Riccio, R., Martin, ...
Get this from a library! Solid-State NMR in zeolite catalysis. [Jun Xu; Qiang Wang; Shenhui Li; Feng Deng] -- Solid-State NMR Characterization of Heterogeneous Catalysts and Catalytic Reactions provides a comprehensive account of state-of-the-art solid-state NMR techniques and the application of these ...
Correlation spectroscopy is one of several types of two-dimensional nuclear magnetic resonance (NMR) spectroscopy. Other types of two-dimensional NMR include J-spectroscopy, exchange spectroscopy (EXSY), and Nuclear Overhauser effect spectroscopy (NOESY.) Two-dimensional NMR spectra provide more information about a molecule than one-dimensional NMR spectra and are especially useful in determining the structure of a molecule, particularly for molecules that are too complicated to work with using one-dimensional NMR. The first two-dimensional experiment, COSY, was proposed by Jean Jeener, a professor at Universit Libre de Bruxelles, in 1971. This experiment was later implemented by Walter P. Aue, Enrico Bartholdi and Richard R. Ernst, who published their work in 19761. A two-dimensional NMR experiment involves a series of one-dimensional experiments. Each experiment consists of a sequence of radio frequency pulses with delay periods in between them. It is the timing, frequencies, and intensities ...
Although conformational changes in TCRs and peptide Ags presented by MHC protein (pMHC) molecules often occur upon binding, their relationship to intrinsic flexibility and role in ligand selectivity are poorly understood. In this study, we used nuclear magnetic resonance to study TCR-pMHC binding, examining recognition of the QL9/H-2Ld complex by the 2C TCR. Although the majority of the CDR loops of the 2C TCR rigidify upon binding, the CDR3β loop remains mobile within the TCR-pMHC interface. Remarkably, the region of the QL9 peptide that interfaces with CDR3β is also mobile in the free pMHC and in the TCR-pMHC complex. Determination of conformational exchange kinetics revealed that the motions of CDR3β and QL9 are closely matched. The matching of conformational exchange in the free proteins and its persistence in the complex enhances the thermodynamic and kinetic stability of the TCR-pMHC complex and provides a mechanism for facile binding. We thus propose that matching of structural ...
Preface XV. 1 Introduction 1. 1.1 Literature 8. 1.2 Units and Constants 9. References 10. Part I Basic Principles and Applications 11. 2 The Physical Basis of the Nuclear Magnetic Resonance Experiment.. Part I 13. 2.1 The Quantum Mechanical Model for the Isolated Proton 13. 2.2 Classical Description of the NMR Experiment 16. 2.3 Experimental Verification of Quantized Angular Momentum and of the Resonance Equation 17. 2.4 The NMR Experiment on Compact Matter and the Principle of the NMR Spectrometer 19. 2.4.1 How to Measure an NMR Spectrum 19. 2.5 Magnetic Properties of Nuclei beyond the Proton 25. References 27. 3 The Proton Magnetic Resonance Spectra of Organic Molecules - Chemical Shift and Spin-Spin Coupling 29. 3.1 The Chemical Shift 29. 3.1.1 Chemical Shift Measurements 32. 3.1.2 Integration of the Spectrum 35. 3.1.3 Structural Dependence of the Resonance Frequency - A General Survey 37. 3.2 Spin-Spin Coupling 41. 3.2.1 Simple Rules for the Interpretation of Multiplet Structures 46. 3.2.2 ...
The ASRC Nuclear Magnetic Resonance Facility features three state-of-the-art Bruker AVANCE III HD NMR spectrometers operating at 600, 700, and 800 MHz suitable for the full complement of biomolecular NMR studies. All three spectrometers are equipped with either cryogenically-cooled or room temperature probes offering a wide range of 1H, 13C, 15N, 19F, 31P, and 2H NMR capabilities.. Equipped with refrigerated sample changers and remote operation capabilities, each of these instruments is able to independently run through 24 (SampleCase) or 600 (SampleJet) samples with limited user involvement.. Additional resources include i) two laser systems dedicated for studies of photoreceptors or other photochemical systems, ii) a high-pressure system for acquiring NMR data at pressures up to 2500 bar, and iii) 1.6-mm HXY magic-angle-spinning (MAS) probe for solid-state NMR experiments, capable of sample MAS rates of up to 40 kHz, for use with the 600 MHz spectrometer.. To view a full list of the ...
Despite their importance for biological activity, slower molecular motions beyond the nanosecond range remain poorly understood. We have assembled an unprecedented set of experimental NMR data, comprising up to 27 residual dipolar couplings per amino acid, to define the nature and amplitude of backbone motion in protein G using the Gaussian axial fluctuation model in three dimensions. Slower motions occur in the loops, and in the beta-sheet, and are absent in other regions of the molecule, including the alpha-helix. In the beta-sheet an alternating pattern of dynamics along the peptide sequence is found to form a long-range network of slow motion in the form of a standing wave extending across the beta-sheet, resulting in maximal conformational sampling at the interaction site. The alternating nodes along the sequence match the alternation of strongly hydrophobic side chains buried in the protein core. Confirmation of the motion is provided through extensive cross-validation and by independent ...
Properties of Mixtures of Cholesterol with Phosphatidylcholine or with Phosphatidylserine Studied by 13C Magic Angle Spinning Nuclear Magnetic Resonance Academic Article ...
31P Nuclear Magnetic Resonance (NMR) Chemical Shifts of 4-TERT.-BUTYL-2,2,6,6-TETRAMETHYL-1-PHENYL-4-PHOSPHORINANOL-1-OXIDE with properties.
Preface XV. 1 Introduction 1. 1.1 Literature 8. 1.2 Units and Constants 9. References 10. Part I Basic Principles and Applications 11. 2 The Physical Basis of the Nuclear Magnetic Resonance Experiment.. Part I 13. 2.1 The Quantum Mechanical Model for the Isolated Proton 13. 2.2 Classical Description of the NMR Experiment 16. 2.3 Experimental Verification of Quantized Angular Momentum and of the Resonance Equation 17. 2.4 The NMR Experiment on Compact Matter and the Principle of the NMR Spectrometer 19. 2.4.1 How to Measure an NMR Spectrum 19. 2.5 Magnetic Properties of Nuclei beyond the Proton 25. References 27. 3 The Proton Magnetic Resonance Spectra of Organic Molecules - Chemical Shift and Spin-Spin Coupling 29. 3.1 The Chemical Shift 29. 3.1.1 Chemical Shift Measurements 32. 3.1.2 Integration of the Spectrum 35. 3.1.3 Structural Dependence of the Resonance Frequency - A General Survey 37. 3.2 Spin-Spin Coupling 41. 3.2.1 Simple Rules for the Interpretation of Multiplet Structures 46. 3.2.2 ...
TY - JOUR. T1 - Quantum correlations and number theory. AU - Boos, H. E.. AU - Korepin, V. E.. AU - Nishiyama, Y.. AU - Shiroishi, M.. PY - 2002/5/24. Y1 - 2002/5/24. N2 - We study the spin-1/2 Heisenberg XXX antiferromagnet for which the spectrum of the Hamiltonian was found by Bethe in 1931. We study the probability of the formation of ferromagnetic string in the antiferromagnetic ground state, which we call emptiness formation probability P(n). This is the most fundamental correlation function. We prove that, for short strings, it can be expressed in terms of the Riemann zeta function with odd arguments, logarithm In 2 and rational coefficients. This adds yet another link between statistical mechanics and number theory. We have obtained an analytical formula for P(5) for the first time. We have also calculated P(n) numerically by the density matrix renormalization group. The results agree quite well with the analytical results. Furthermore, we study the asymptotic behaviour of P(n) at finite ...
Spectral resolution in proton NMR spectroscopy is reduced by the splitting of resonances into multiplets due to the effect of homonuclear scalar couplings. Although these effects are often hidden in protein NMR spectroscopy by low digital resolution and routine apodization, behind the scenes homonuclear scalar couplings increase spectral overcrowding. The possibilities for biomolecular NMR offered by new pure shift NMR methods are illustrated here. Both resolution and sensitivity are improved, without any increase in experiment time. In these experiments, free induction decays are collected in short bursts of data acquisition, with durations short on the timescale of J-evolution, interspersed with suitable refocusing elements. The net effect is real-time (t (2)) broadband homodecoupling, suppressing the multiplet structure caused by proton-proton interactions. The key feature of the refocusing elements is that they discriminate between the resonances of active (observed) and passive (coupling ...
The NMR team (Manfred Wagner and Robert Graf) is inviting all of you interested in NMR to a series of short lectures on NMR spectroscopy given from April 3rd to April 5th 2017 in the Staudinger hall.. 3.4.2017. 9.30 - 10.30: 1. Introduction to NMR Spectroscopy. 10.45 - 11.45: 2. Quantitative NMR Spectroscopy (qNMR). 13.30 - 14.30: 3. Heteronuclear NMR (1D). 14.45 - 15.45: 4. 2D COSY, NOESY, TOCSY, ROESY….. 4.4.2017. 9.30 - 10.30: 5. 2D HSQC, HMQC, HMBC, HSQC-NOESY….. 10.45 - 11.45: 6. Diffusion NMR. 13.30 - 14.30: 7. Distance Determination via NMR Spectroscopy. 14.45 - 15.45: 8. Relaxation Measurements (T1, T2), Dynamic, Mobility….. 5.4.2017. 9.30 - 10.30: 9. Introduction to Solid State NMR Spectroscopy. 10.45 - 11.45: 10. Some Basic Experiments: CP-MAS, Double-Quantum NMR, …. 13.00 - 14.00: 11. Molecular Motions in the Solid State. ...
The ultra-fast magic angle spinning capabilities of Brukers 111 kHz MAS probe allows for the direct and high resolution observation of proton resonances from complex biomolecules, stated Professor Lyndon Emsley from the Ecole Normale Supérieure de Lyon, France. He continued: We get double the resolution in protonated samples compared to 60 kHz spinning, and we were especially pleased to obtain a 1 GHz version of this break-through MAS probe, with which we have measured never-before-seen ultra-high field, ultra-fast MAS data. As such, it is a great new tool in our solid-state NMR arsenal for the structure determination of proteins, a critical need for studying disease mechanisms ...
Chemical shift perturbation (CSP, chemical shift mapping or complexation-induced modifications in chemical shift, CIS) follows modifications within the chemical shifts of a protein when a ligand is added, and makes use of these to decide the placement of the binding web site, the affinity of the ligand, and/or presumably the construction of the advanced. A key consider figuring out the looks of spectra throughout a titration is the change price between free and certain, or extra particularly the off-rate koff. When koff is bigger than the chemical shift distinction between free and certain, which generally equates to an affinity Kd weaker than about 3μM, then change is quick on the chemical shift timescale.. Under these circumstances, the noticed shift is the population-weighted common of free and certain, which permits Kd to be decided from measurement of peak positions, offered the measurements are made appropriately. (1)H shifts are influenced to a big extent by through-space interactions, ...
Strukturer af Supramolekylær protein forsamlinger på atomare opløsning er for høj relevans på grund af deres afgørende roller i en...