Abstract Nitrogen-15 Carr-Purcell-Meiboom-Gill (CPMG) transverse relaxation experiment are widely used to characterize protein backbone dynamics and chemical exchange parameters. Although an accurate value of the transverse relaxation rate, R2, is needed for accurate characterization of dynamics, the uncertainty in the R2 value depends on the experimental settings and the details of the data analysis itself. Here, we present an analysis of the impact of CPMG pulse phase alternation on the accuracy of the 15N CPMG R2. Our simulations show that R2 can be obtained accurately for a relatively wide spectral width, either using the conventional phase cycle or using phase alternation when the r.f. pulse power is accurately calibrated. However, when the r.f. pulse is miscalibrated, the conventional CPMG experiment exhibits more significant uncertainties in R2 caused by the off-resonance effect than does the phase alternation experiment. Our experiments show that this effect becomes manifest under the circumstance that the systematic error exceeds that arising from experimental noise. Furthermore, our results provide the means to estimate practical parameter settings that yield accurate values of 15N transverse relaxation rates in the both CPMG experiments.
Content Type Journal Article
Category Article
Pages 1-11
DOI 10.1007/s10858-012-9621-x
Authors
Wazo Myint, Department of Structural Biology, University of Pittsburgh School of Medicine, Rm 1037, Biomedical Science Tower 3, 3501 Fifth Avenue, Pittsburgh, PA 15260, USA
Yufeng Cai, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01605, USA
Celia A. Schiffer, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01605, USA
Rieko Ishima, Department of Structural Biology, University of Pittsburgh School of Medicine, Rm 1037, Biomedical Science Tower 3, 3501 Fifth Avenue, Pittsburgh, PA 15260, USA
Water proton spin saturation affects measured protein backboneN spin relaxation rates
Water proton spin saturation affects measured protein backboneN spin relaxation rates
Publication year: 2011
Source: Journal of Magnetic Resonance, Available online 1 October 2011</br>
Kang*Chen, Nico*Tjandra</br>
Protein backboneN NMR spin relaxation rates are useful in characterizing the protein dynamics and structures. To observe the protein nuclear-spin resonances a pulse sequence has to include a water suppression scheme. There are two commonly employed methods, saturating or dephasing the water spins with pulse field gradients and keeping them unperturbed with flip-back pulses....
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Translational Diffusion of Macromolecular Assemblies Measured Using Transverse-Relaxation-Optimized Pulsed Field Gradient NMR
Translational Diffusion of Macromolecular Assemblies Measured Using Transverse-Relaxation-Optimized Pulsed Field Gradient NMR
Reto Horst, Arthur L. Horwich and Kurt Wu?thrich
http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jacsat/0/jacsat.ahead-of-print/ja206531c/aop/images/medium/ja-2011-06531c_0003.gif
Journal of the American Chemical Society
DOI: 10.1021/ja206531c
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Translational diffusion of macromolecular assemblies measured using transverse relaxation-optimized PFG-NMR.
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J Am Chem Soc. 2011 Sep 16;
Authors: Horst R, Horwich AL, Wüthrich K
Abstract
ABSTRACT In structural biology, pulsed field gradient (PFG) NMR for characterization of size and hydrodynamic parameters of macromolecular solutes has the advantage over other techniques that the measurements can be recorded with identical solution...
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Quantitative comparison of errors in 15N transverse relaxation rates measured using various CPMG phasing schemes
Linear Mode
