Title
Quantitative comparison of errors in 15N transverse relaxation rates measured using various CPMG phasing schemes
UMMS Affiliation
Department of Biochemistry and Molecular Pharmacology
Publication Date
2012-5
Document Type
Article
Subjects
Molecular Dynamics Simulation; Monte Carlo Method; Nitrogen Isotopes; Nuclear Magnetic Resonance, Biomolecular; Proteins
Disciplines
Biochemistry, Biophysics, and Structural Biology | Pharmacology, Toxicology and Environmental Health
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, R(2), is needed for accurate characterization of dynamics, the uncertainty in the R(2) 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 (15)N CPMG R(2). Our simulations show that R(2) 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 R(2) 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 (15)N transverse relaxation rates in the both CPMG experiments.
DOI of Published Version
10.1007/s10858-012-9621-x
Source
J Biomol NMR. 2012 May;53(1):13-23. Epub 2012 Apr 1. Link to article on publisher's site
Journal/Book/Conference Title
Journal of biomolecular NMR
Related Resources
PubMed ID
22466935
Repository Citation
Myint, Wazo; Cai, Yufeng; Schiffer, Celia A.; and Ishima, Rieko, "Quantitative comparison of errors in 15N transverse relaxation rates measured using various CPMG phasing schemes" (2012). Biochemistry and Molecular Pharmacology Publications and Presentations. 150.
https://escholarship.umassmed.edu/bmp_pp/150