Microsecond protein dynamics measured by C-13(alpha) rotating-frame spin relaxation
2005 (English)In: ChemBioChem (Print), ISSN 1439-4227, Vol. 6, no 9, 1685-1692 p.Article in journal (Refereed) Published
NMR spin relaxation in the rotating frame (R-1p) is a unique method for atomic-resolution characterisation of conformational (chemical) exchange processes occuring on the microsecond timescale. We present a rotating frame C-13 relaxation dispersion experiment for measuring conformational dynamics in uniformly C-13-labeled proteins. The experiment was validated by using the E140Q mutant of the C-terminal fragment of calmodulin, which exhibits significant conformational exchange between two major conformations, as gauged from previous N-15 and H-1 relaxation studies. Consistent with previous work, the present C-13, R-1p experiment detects conformational-exchange dynamics throughout the protein. The average correlation time of <tau(ex)> = 25 +/- 8 mu s is in excellent agreement with those determined previously from H-1 and N-15 R-1p, relaxation data: <tau(ex)> = 19 +/- 7 and 21 +/- 3 mu s, respectively. The extracted chemical-shift differences between the exchanging states reveal significant fluctuations in dihedral angles within single regions of Ramachandran phi-psi space that were not identified from the H-1 and N-15 relaxation data. The present results underscore the advantage of using several types of nuclei to probe exchange dynamics in biomolecules.
Place, publisher, year, edition, pages
2005. Vol. 6, no 9, 1685-1692 p.
C-TERMINAL DOMAIN; CONFORMATIONAL EXCHANGE; TRANSVERSE RELAXATION; BACKBONE DYNAMICS; CHEMICAL-SHIFTS; NMR-SPECTROSCOPY; ORDER PARAMETERS; TIME-SCALE; CALMODULIN; RESONANCE
IdentifiersURN: urn:nbn:se:liu:diva-51907DOI: 10.1002/cbic.200500086OAI: oai:DiVA.org:liu-51907DiVA: diva2:278089