The Experts below are selected from a list of 255 Experts worldwide ranked by ideXlab platform
Goran Widmalm - One of the best experts on this subject based on the ideXlab platform.
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glycan flexibility insights into nanosecond dynamics from a microsecond molecular dynamics simulation explaining an unusual Nuclear Overhauser Effect
Carbohydrate Research, 2010Co-Authors: Jens Landstrom, Goran WidmalmAbstract:An atomistic all-atom molecular dynamics simulation of the trisaccharide beta-D-ManpNAc-(1-->4)[alpha-D-Glcp-(1-->3)]-alpha-L-Rhap-OMe with explicit solvent molecules has been carried out. The trisaccharide represents a model for the branching region of the O-chain polysaccharide of a strain from Aeromonas salmonicida. The extensive MD simulations having a 1-micros duration revealed a conformational dynamics process on the nanosecond time scale, that is, a 'time window' not extensively investigated for carbohydrates to date. The results obtained from the MD simulation underscore the predictive power of molecular simulations in studies of biomolecular systems and also explain an unusual Nuclear Overhauser Effect originating from conformational exchange.
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a conformational study of the vicinally branched trisaccharide d glcp 1 2 d glcp 1 3 d manp ome by Nuclear Overhauser Effect spectroscopy noesy and transverse rotating frame Overhauser Effect spectroscopy troesy experiments comparison to monte carlo
Biopolymers, 1999Co-Authors: Alexandra Kjellberg, Goran WidmalmAbstract:The trisaccharide beta-D-Glcp-(1 --> 2)[beta-D-Glcp-(1 --> 3)]alpha-D-Manp-OMe, a model for branching regions in oligosaccharides, has been investigated by one-dimensional DPFGSE (1)H, (1)H Nuclear Overhauser Effect spectroscopy (NOESY) and transverse rotating-frame Overhauser Effect spectroscopy (TROESY) experiments at 30 degrees C in water and in the solvent mixture water : dimethyl sulfoxide (7 : 3). Cross-relaxation rates were obtained from the nmr experiments and interpreted as proton-proton distances. From Metropolis Monte Carlo and Langevin dynamics simulations, distances were calculated and compared to those obtained from experiment. Using the previously determined dynamics from carbon-13 nmr relaxation measurements of the trisaccharide in the solvent mixture, intraresidue proton distances could be obtained that were in excellent to reasonable agreement with those calculated from simulations. In water, the isolated spin-pair approximation was used for comparison of interproton distances. The experimentally derived distances in both solvents showed that the trans-glycosidic distances were shorter between the anomeric proton of the glucosyl group and the proton at the linkage position, respectively, than to the proton on the adjacent carbon on the mannosyl residue. The interresidue distances calculated from the computer simulations, performed with three different force fields, namely HSEA, PARM22, and CHEAT95, resulted in the reverse order in all cases but one.
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a conformational study of the vicinally branched trisaccharide beta d glcp 1 2 beta d glcp 1 3 alpha d manp ome by Nuclear Overhauser Effect spectroscopy noesy and transverse rotating frame Overhauser Effect spectroscopy troesy experiments comparison
Biopolymers, 1999Co-Authors: Alexandra Kjellberg, Goran WidmalmAbstract:The trisaccharide beta-D-Glcp-(1 --> 2)[beta-D-Glcp-(1 --> 3)]alpha-D-Manp-OMe, a model for branching regions in oligosaccharides, has been investigated by one-dimensional DPFGSE (1)H, (1)H Nuclear Overhauser Effect spectroscopy (NOESY) and transverse rotating-frame Overhauser Effect spectroscopy (TROESY) experiments at 30 degrees C in water and in the solvent mixture water : dimethyl sulfoxide (7 : 3). Cross-relaxation rates were obtained from the nmr experiments and interpreted as proton-proton distances. From Metropolis Monte Carlo and Langevin dynamics simulations, distances were calculated and compared to those obtained from experiment. Using the previously determined dynamics from carbon-13 nmr relaxation measurements of the trisaccharide in the solvent mixture, intraresidue proton distances could be obtained that were in excellent to reasonable agreement with those calculated from simulations. In water, the isolated spin-pair approximation was used for comparison of interproton distances. The experimentally derived distances in both solvents showed that the trans-glycosidic distances were shorter between the anomeric proton of the glucosyl group and the proton at the linkage position, respectively, than to the proton on the adjacent carbon on the mannosyl residue. The interresidue distances calculated from the computer simulations, performed with three different force fields, namely HSEA, PARM22, and CHEAT95, resulted in the reverse order in all cases but one.
Alexandra Kjellberg - One of the best experts on this subject based on the ideXlab platform.
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a conformational study of the vicinally branched trisaccharide d glcp 1 2 d glcp 1 3 d manp ome by Nuclear Overhauser Effect spectroscopy noesy and transverse rotating frame Overhauser Effect spectroscopy troesy experiments comparison to monte carlo
Biopolymers, 1999Co-Authors: Alexandra Kjellberg, Goran WidmalmAbstract:The trisaccharide beta-D-Glcp-(1 --> 2)[beta-D-Glcp-(1 --> 3)]alpha-D-Manp-OMe, a model for branching regions in oligosaccharides, has been investigated by one-dimensional DPFGSE (1)H, (1)H Nuclear Overhauser Effect spectroscopy (NOESY) and transverse rotating-frame Overhauser Effect spectroscopy (TROESY) experiments at 30 degrees C in water and in the solvent mixture water : dimethyl sulfoxide (7 : 3). Cross-relaxation rates were obtained from the nmr experiments and interpreted as proton-proton distances. From Metropolis Monte Carlo and Langevin dynamics simulations, distances were calculated and compared to those obtained from experiment. Using the previously determined dynamics from carbon-13 nmr relaxation measurements of the trisaccharide in the solvent mixture, intraresidue proton distances could be obtained that were in excellent to reasonable agreement with those calculated from simulations. In water, the isolated spin-pair approximation was used for comparison of interproton distances. The experimentally derived distances in both solvents showed that the trans-glycosidic distances were shorter between the anomeric proton of the glucosyl group and the proton at the linkage position, respectively, than to the proton on the adjacent carbon on the mannosyl residue. The interresidue distances calculated from the computer simulations, performed with three different force fields, namely HSEA, PARM22, and CHEAT95, resulted in the reverse order in all cases but one.
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a conformational study of the vicinally branched trisaccharide beta d glcp 1 2 beta d glcp 1 3 alpha d manp ome by Nuclear Overhauser Effect spectroscopy noesy and transverse rotating frame Overhauser Effect spectroscopy troesy experiments comparison
Biopolymers, 1999Co-Authors: Alexandra Kjellberg, Goran WidmalmAbstract:The trisaccharide beta-D-Glcp-(1 --> 2)[beta-D-Glcp-(1 --> 3)]alpha-D-Manp-OMe, a model for branching regions in oligosaccharides, has been investigated by one-dimensional DPFGSE (1)H, (1)H Nuclear Overhauser Effect spectroscopy (NOESY) and transverse rotating-frame Overhauser Effect spectroscopy (TROESY) experiments at 30 degrees C in water and in the solvent mixture water : dimethyl sulfoxide (7 : 3). Cross-relaxation rates were obtained from the nmr experiments and interpreted as proton-proton distances. From Metropolis Monte Carlo and Langevin dynamics simulations, distances were calculated and compared to those obtained from experiment. Using the previously determined dynamics from carbon-13 nmr relaxation measurements of the trisaccharide in the solvent mixture, intraresidue proton distances could be obtained that were in excellent to reasonable agreement with those calculated from simulations. In water, the isolated spin-pair approximation was used for comparison of interproton distances. The experimentally derived distances in both solvents showed that the trans-glycosidic distances were shorter between the anomeric proton of the glucosyl group and the proton at the linkage position, respectively, than to the proton on the adjacent carbon on the mannosyl residue. The interresidue distances calculated from the computer simulations, performed with three different force fields, namely HSEA, PARM22, and CHEAT95, resulted in the reverse order in all cases but one.
Brian D Sykes - One of the best experts on this subject based on the ideXlab platform.
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interaction of troponin i and troponin c use of the two dimensional Nuclear magnetic resonance transferred Nuclear Overhauser Effect to determine the structure of the inhibitory troponin i peptide when bound to skeletal troponin c
Journal of Molecular Biology, 1991Co-Authors: A P Campbell, Brian D SykesAbstract:Abstract We have used two-dimensional 1 H Nuclear magnetic resonance spectroscopy to determine the structure of the synthetic inhibitory peptide N α-acetyl TnI(104–115) amide bound to calcium-saturated skeletal troponin C (TnC). Conformational changes in the peptide induced by the formation of the troponin I (TnI) peptide-TnC complex were followed by the study of the transferred Nuclear Overhauser Effect, a technique that allows one to determine the structure of a ligand bound to a macromolecule. The structure of the bound TnI peptide reveals an amphiphilic α-helix, distorted around the two central proline residues. The central bend in the peptide functions to bring the residues on the hydrophobic face into closer proximity with each other, thereby forming a small hydrophobic pocket. The hydrophilic, basic residues extend off the opposite face of the peptide. Hydrophobic surfaces on TnC that become exposed upon binding of calcium are involved in the binding of the TnI peptide, but electrostatic interactions also contribute to the strength of the interaction. The role of amphiphilic helices in the targeting of calcium-binding proteins such as troponin C will be discussed.
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theoretical evaluation of the two dimensional transferred Nuclear Overhauser Effect
Journal of Magnetic Resonance, 1991Co-Authors: Patricia A Campbell, Brian D SykesAbstract:Abstract A theoretical evaluation of the two-dimensional intramolecular transferred Nuclear Overhauser Effect (TRNOE) is presented using a full relaxation matrix approach. The application of this analysis to the study of 6-24 residue peptides binding to proteins ranging in size from 18,000 to 80,000 Da is considered. The Effects of variables such as mixing time, fraction of bound peptide, free and bound correlation times, and other contributions to spin-lattice relaxation rates are examined in an attempt to offer practical experimental guidelines for the design of a TRNOE experiment.
Mingsheng Zhan - One of the best experts on this subject based on the ideXlab platform.
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enhancement of solid state proton nmr via the spin polarization induced Nuclear Overhauser Effect with laser polarized xenon
Physical Review B, 2004Co-Authors: Xin Zhou, Jun Luo, Xianping Sun, Xizhi Zeng, Shangwu Ding, Maili Liu, Mingsheng ZhanAbstract:We have successfully transferred the spin polarization of laser-polarized Xe-129 to the proton spins of solid-state (HCl)-H-1 via spin polarization-induced Nuclear Overhauser Effect (SPINOE). The key steps include mixing the laser-polarized Xe-129 gas with the (HCl)-H-1 gas and cooling them to their condensed state in a flow system. The solid-state Nuclear magnetic resonance (NMR) signal enhancement factor of 6 for H-1 was observed, compared with the Boltzmann polarization signal at 1.879 T and 142 K. This method may be valuable for applications in both NMR spectroscopy and chemical physics.
Kevin M Brindle - One of the best experts on this subject based on the ideXlab platform.
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quantitation of a spin polarization induced Nuclear Overhauser Effect spinoe between a hyperpolarized 13 c labeled cell metabolite and water protons
Contrast Media & Molecular Imaging, 2014Co-Authors: Irene Marcorius, Sarah E Bohndiek, Mikko I Kettunen, Timothy J Larkin, Meer Basharat, Colm Seeley, Kevin M BrindleAbstract:The spin polarization-induced Nuclear Overhauser Effect (SPINOE) describes the enhancement of spin polarization of solvent nuclei by the hyperpolarized spins of a solute. In this communication we demonstrate that SPINOEs can be observed between [1,4-13C2]fumarate, hyperpolarized using the dissolution dynamic Nuclear polarization technique, and solvent water protons. We derive a theoretical expression for the expected enhancement and demonstrate that this fits well with experimental measurements. Although the magnitude of the Effect is relatively small (around 2% measured here), the SPINOE increases at lower field strengths, so that at clinically relevant magnetic fields (1.5–3 T) it may be possible to track the passage through the circulation of a bolus containing a hyperpolarized 13C-labeled substrate through the increase in solvent water 1H signal. © 2014 The Authors. Contrast Media & Molecular Imaging published by John Wiley and Sons, Ltd.
