CPMG relaxation dispersion NMR experiments measuring glycine H-1(alpha) and C-13(alpha) chemical shifts in the 'invisible' excited states of proteins
2009 (English)In: Journal of Biomolecular NMR, ISSN 0925-2738, E-ISSN 1573-5001, Vol. 45, no 1-2, 45-55 p.Article in journal (Refereed) Published
Carr-Purcell-Meiboom-Gill (CPMG) relaxation dispersion NMR experiments are extremely powerful for characterizing millisecond time-scale conformational exchange processes in biomolecules. A large number of such CPMG experiments have now emerged for measuring protein backbone chemical shifts of sparsely populated (> 0.5%), excited state conformers that cannot be directly detected in NMR spectra and that are invisible to most other biophysical methods as well. A notable deficiency is, however, the absence of CPMG experiments for measurement of H-1(alpha) and C-13(alpha) chemical shifts of glycine residues in the excited state that reflects the fact that in this case the H-1(alpha), C-13(alpha) spins form a three-spin system that is more complex than the AX H-1(alpha)-C-13(alpha) spin systems in the other amino acids. Here pulse sequences for recording H-1(alpha) and C-13(alpha) CPMG relaxation dispersion profiles derived from glycine residues are presented that provide information from which H-1(alpha), C-13(alpha) chemical shifts can be obtained. The utility of these experiments is demonstrated by an application to a mutant of T4 lysozyme that undergoes a millisecond time-scale exchange process facilitating the binding of hydrophobic ligands to an internal cavity in the protein.
Place, publisher, year, edition, pages
2009. Vol. 45, no 1-2, 45-55 p.
CPMG, Relaxation dispersion, Excited protein states, T4 lysozyme, Millisecond dynamics
IdentifiersURN: urn:nbn:se:liu:diva-85037DOI: 10.1007/s10858-009-9310-6PubMedID: 19319480OAI: oai:DiVA.org:liu-85037DiVA: diva2:563733