A methyl Transverse Relaxation Optimized Spectroscopy (methyl-TROSY) based, multiple quantum (MQ) 13C Carr-Purcell-Meiboom-Gill (CPMG) relaxation dispersion NMR experiment is described. The experiment is derived from the previously developed MQ 13Câ??1H CPMG scheme (Korzhnev in J Am Chem Soc 126: 3964â??73, 2004) supplemented with a CPMG train of refocusing 1H pulses applied with constant frequency and synchronized with the 13C CPMG pulse train. The optimal 1H â??decouplingâ?? scheme that minimizes the amount of fast-relaxing methyl MQ magnetization present during CPMG intervals, makes use of an XY-4 phase cycling of the refocusing composite 1H pulses. For small-to-medium sized proteins, the MQ 13C CPMG experiment has the advantage over its single quantum (SQ) 13C counterpart of significantly reducing intrinsic, exchange-free relaxation rates of methyl coherences. For high molecular weight proteins, the MQ 13C CPMG experiment eliminates complications in the interpretation of MQ 13Câ??1H CPMG relaxation dispersion profiles arising from contributions to exchange from differences in methyl 1H chemical shifts between ground and excited states. The MQ 13C CPMG experiment is tested on two protein systems: (1) a triple mutant of the Fyn SH3 domain that interconverts slowly on the chemical shift time scale between the major folded state and an excited state folding intermediate; and (2) the 82-kDa enzyme Malate Synthase G (MSG), where chemical exchange at individual Ile δ1 methyl positions occurs on a much faster time-scale.
[NMR paper] A methyl-TROSY based 13C relaxation dispersion NMR experiment for studies of chemical exchange in proteins
A methyl-TROSY based 13C relaxation dispersion NMR experiment for studies of chemical exchange in proteins
A methyl Transverse Relaxation Optimized Spectroscopy (methyl-TROSY) based, multiple quantum (MQ) ^(13)C Carr-Purcell-Meiboom-Gill (CPMG) relaxation dispersion NMR experiment is described. The experiment is derived from the previously developed MQ ^(13)C-ąH CPMG scheme (Korzhnev in J Am Chem Soc 126: 3964-73, 2004) supplemented with a CPMG train of refocusing ąH pulses applied with constant frequency and synchronized with the ^(13)C CPMG pulse train. The optimal ąH 'decoupling' scheme...
Quantitative measurement of exchange dynamics in proteins via 13 C relaxation dispersion of 13 CHD 2 -labeled samples
Quantitative measurement of exchange dynamics in proteins via 13 C relaxation dispersion of 13 CHD 2 -labeled samples
Abstract
Methyl groups have emerged as powerful probes of protein dynamics with timescales from picoseconds to seconds. Typically, studies involving high molecular weight complexes exploit 13CH3- or 13CHD2-labeling in otherwise highly deuterated proteins. The 13CHD2 label offers the unique advantage of providing 13C, 1H and 2H spin probes, however a disadvantage has been the lack of an experiment to record 13C...
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06-02-2016 02:11 AM
Assessment of chemical exchange in tryptophanâ??albumin solution through 19 F multicomponent transverse relaxation dispersion analysis
Assessment of chemical exchange in tryptophanâ??albumin solution through 19 F multicomponent transverse relaxation dispersion analysis
Abstract
A number of NMR methods possess the capability of probing chemical exchange dynamics in solution. However, certain drawbacks limit the applications of these NMR approaches, particularly, to a complex system. Here, we propose a procedure that integrates the regularized nonnegative least squares (NNLS) analysis of multiexponential T2 relaxation into Carrâ??Purcellâ??Meiboomâ??Gill (CPMG) relaxation dispersion...
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04-22-2015 12:40 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
Conformational exchange of aromatic side chains characterized by L-optimized TROSY-selected 13C CPMG relaxation dispersion
Conformational exchange of aromatic side chains characterized by L-optimized TROSY-selected 13C CPMG relaxation dispersion
Abstract Protein dynamics on the millisecond time scale commonly reflect conformational transitions between distinct functional states. NMR relaxation dispersion experiments have provided important insights into biologically relevant dynamics with site-specific resolution, primarily targeting the protein backbone and methyl-bearing side chains. Aromatic side chains represent attractive probes of protein dynamics because they are over-represented in protein binding...
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07-30-2012 07:42 AM
TROSY-selected ZZ-exchange experiment for characterizing slow chemical exchange in large proteins
TROSY-selected ZZ-exchange experiment for characterizing slow chemical exchange in large proteins
Abstract A TROSY-selected ZZ-exchange experiment is described for measuring slow chemical exchange rates by monitoring the TROSY component of 15N longitudinal magnetization. Application of the proposed pulse sequence to the cadherin 8 N-terminal extracelluar domain demonstrates that enhanced sensitivity is obtained, compared to a previously described TROSY-detected ZZ-exchange sequence (Sahu et al. J Am Chem Soc 129: 13232â??13237, 2007), by preserving the TROSY effect during the mixing...
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01-09-2011 12:46 PM
Suite of Six NMR Relaxation Dispersion Experiments to Study Multiple-Site Exchange in Proteins
http://pubs.acs.org/isubscribe/journals/jacsat/127/i44/figures/ja054550en00001.gif
Multiple-Site Exchange in Proteins Studied with a Suite of Six NMR Relaxation Dispersion Experiments: An Application to the Folding of a Fyn SH3 Domain Mutant
Dmitry M. Korzhnev, Philipp Neudecker, Anthony Mittermaier, Vladislav Yu. Orekhov, and Lewis E. Kay*
Contribution from the Departments of Medical Genetics, Biochemistry, and Chemistry, The University of Toronto, Toronto, Ontario M5S 1A8, Canada, and Swedish NMR Center at Göteborg University, Box 465, 405 30 Göteborg, Sweden
J. Am. Chem....
A methyl-TROSY based 13C relaxation dispersion NMR experiment for studies of chemical exchange in proteins
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