A cross-polarization based rotating-frame separated-local-field NMR experiment under ultrafast MAS conditions.
J Magn Reson. 2014 Nov 15;250C:37-44
Authors: Zhang R, Damron J, Vosegaard T, Ramamoorthy A
Abstract
Rotating-frame separated-local-field solid-state NMR experiments measure highly resolved heteronuclear dipolar couplings which, in turn, provide valuable interatomic distances for structural and dynamic studies of molecules in the solid-state. Though many different rotating-frame SLF sequences have been put forth, recent advances in ultrafast MAS technology have considerably simplified pulse sequence requirements due to the suppression of proton-proton dipolar interactions. In this study we revisit a simple two-dimensional (1)H-(13)C dipolar coupling/chemical shift correlation experiment using (13)C detected cross-polarization with a variable contact time (CPVC) and systematically study the conditions for its optimal performance at 60kHz MAS. In addition, we demonstrate the feasibility of a proton-detected version of the CPVC experiment. The theoretical analysis of the CPVC pulse sequence under different Hartmann-Hahn matching conditions confirms that it performs optimally under the ZQ (w1H-w1C=±wr) condition for polarization transfer. The limits of the cross polarization process are explored and precisely defined as a function of offset and Hartmann-Hahn mismatch via spin dynamics simulation and experiments on a powder sample of uniformly (13)C-labeled L-isoleucine. Our results show that the performance of the CPVC sequence and subsequent determination of (1)H-(13)C dipolar couplings are insensitive to (1)H/(13)C frequency offset frequency when high RF fields are used on both RF channels. Conversely, the CPVC sequence is quite sensitive to the Hartmann-Hahn mismatch, particularly for systems with weak heteronuclear dipolar couplings. We demonstrate the use of the CPVC based SLF experiment as a tool to identify different carbon groups, and hope to motivate the exploration of more sophisticated (1)H detected avenues for ultrafast MAS.
PMID: 25486635 [PubMed - as supplied by publisher]
[NMR paper] Slow motions in microcrystalline proteins as observed by MAS-dependent (15)N rotating-frame NMR relaxation.
Slow motions in microcrystalline proteins as observed by MAS-dependent (15)N rotating-frame NMR relaxation.
Related Articles Slow motions in microcrystalline proteins as observed by MAS-dependent (15)N rotating-frame NMR relaxation.
J Magn Reson. 2014 Sep 20;248C:8-12
Authors: Krushelnitsky A, Zinkevich T, Reif B, Saalwächter K
Abstract
(15)N NMR relaxation rate R1? measurements reveal that a substantial fraction of residues in the microcrystalline chicken alpha-spectrin SH3 domain protein undergoes dynamics in the ?s-ms...
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10-06-2014 12:37 PM
[NMR paper] Slow motions in microcrystalline proteins as observed by MAS-dependent 15N rotating-frame NMR relaxation
Slow motions in microcrystalline proteins as observed by MAS-dependent 15N rotating-frame NMR relaxation
Publication date: Available online 20 September 2014
Source:Journal of Magnetic Resonance</br>
Author(s): Alexey Krushelnitsky , Tatiana Zinkevich , Bernd Reif , Kay Saalwächter</br>
15N NMR relaxation rate R 1? measurements reveal that a substantial fraction of residues in the microcrystalline chicken alpha-spectrin SH3 domain protein undergoes dynamics in the ?s - ms timescale range. On the basis of a comparison of 2D site-resolved with 1D integrated 15N...
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09-20-2014 07:51 PM
Exploiting level anti-crossings (LACs) in the rotating frame for transferring spin hyperpolarization
From The DNP-NMR Blog:
Exploiting level anti-crossings (LACs) in the rotating frame for transferring spin hyperpolarization
Pravdivtsev, A.N., et al., Exploiting level anti-crossings (LACs) in the rotating frame for transferring spin hyperpolarization. Phys Chem Chem Phys, 2014. 16(35): p. 18707-19.
http://www.ncbi.nlm.nih.gov/pubmed/24870026
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08-20-2014 02:06 PM
[NMR paper] Multiple acquisition/multiple observation separated local field/chemical shift correlation solid-state magic angle spinning NMR spectroscopy.
Multiple acquisition/multiple observation separated local field/chemical shift correlation solid-state magic angle spinning NMR spectroscopy.
Multiple acquisition/multiple observation separated local field/chemical shift correlation solid-state magic angle spinning NMR spectroscopy.
J Magn Reson. 2014 Jun 28;245C:98-104
Authors: Das BB, Opella SJ
Abstract
Multiple acquisition spectroscopy (MACSY) experiments that enable multiple free induction decays to be recorded during individual experiments are demonstrated. In...
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07-16-2014 10:46 AM
Off-resonance rotating-frame relaxation dispersion experiment for 13C in aromatic side chains using L-optimized TROSY-selection
Off-resonance rotating-frame relaxation dispersion experiment for 13C in aromatic side chains using L-optimized TROSY-selection
Abstract
Protein dynamics on the microsecondâ??millisecond time scales often play a critical role in biological function. NMR relaxation dispersion experiments are powerful approaches for investigating biologically relevant dynamics with site-specific resolution, as shown by a growing number of publications on enzyme catalysis, protein folding, ligand binding, and allostery. To date, the majority of studies has probed the...
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06-19-2014 10:21 PM
Hydration water dynamics in biopolymers from NMR relaxation in the rotating frame.
Hydration water dynamics in biopolymers from NMR relaxation in the rotating frame.
Related Articles Hydration water dynamics in biopolymers from NMR relaxation in the rotating frame.
J Magn Reson. 2010 Sep 24;
Authors: Blicharska B, Peemoeller H, Witek M
Assuming dipole-dipole interaction as the dominant relaxation mechanism of protons of water molecules adsorbed onto macromolecule (biopolymer) surfaces we have been able to model the dependences of relaxation rates on temperature and frequency. For adsorbed water molecules the correlation times are...
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10-22-2010 04:33 PM
[NMR paper] Off-resonance rotating frame spin-lattice NMR relaxation studies of phosphorus metabo
Off-resonance rotating frame spin-lattice NMR relaxation studies of phosphorus metabolite rotational diffusion in bovine lens homogenates.
Related Articles Off-resonance rotating frame spin-lattice NMR relaxation studies of phosphorus metabolite rotational diffusion in bovine lens homogenates.
Biochemistry. 1990 Aug 21;29(33):7547-57
Authors: Caines GH, Schleich T, Morgan CF, Farnsworth PN
The rotational diffusion behavior of phosphorus metabolites present in calf lens cortical and nuclear homogenates was investigated by the NMR technique of...
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08-21-2010 11:04 PM
1H-13C Separated Local Field Spectroscopy of Uniformly 13C Labeled Peptides and Prote
1H-13C Separated Local Field Spectroscopy of Uniformly 13C Labeled Peptides and Proteins
Publication year: 2010
Source: Journal of Magnetic Resonance, In Press, Accepted Manuscript, Available online 1 July 2010</br>
Eugene C., Lin , Chin H., Wu , Yuan, Yang , Christopher V., Grant , Stanley J., Opella</br>
By incorporating homonuclear decoupling on both the 1H and 13C channels it is feasible to obtain high-resolution two-dimensional separated local field spectra of peptides and proteins that are 100% labeled with 13C. Dual-PISEMO (Polarization Inversion Spin Exchange Modulated...
A cross-polarization based rotating-frame separated-local-field NMR experiment under ultrafast MAS conditions.
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