ISSN:
1573-5001
Keywords:
backbone dynamics
;
conformational exchange
;
proteins
;
relaxation
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
Abstract The systematic difference between T 2 values obtained from CPMG and T 1ρ experiments was observed for backbone 15N nuclei of bacterial ribonuclease barnase. Theoretical consideration suggests that the observed difference is caused by off-resonance effects of 180° pulses of the CPMG pulse train. Namely, at off-resonance conditions T 1-dependent secondary echo coherence pathways considerably contribute to the signal decay in the CPMG experiment and result in systematic (up to 10%) offset-dependent overestimation of 15N T 2 measured by the CPMG technique. Under certain circumstances off-resonance effects result in dependence of 15N T 2 on CPMG frequency, which might be erroneously interpreted as conformational exchange on the millisecond time-scale. A procedure for numerical correction of 15N T 2 (CPMG) data is proposed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1008348827208
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