Observation and relaxation properties of individual fast-relaxing proton transitions in [13CH3]-methyl-labeled, deuterated proteins

• Published in: Journal of magnetic resonance (1997) 2012-04, Vol.217, p.100-105
• Main Authors: Sun, Hechao, Tugarinov, Vitali
• Format: Article
• Language: English
• Subjects: Cross-correlated spin relaxation; Deuterium - chemistry; Deuterium Exchange Measurement - methods; Magnetic Resonance Spectroscopy - methods; Magnetically equivalent spin-systems; Methane - analogs & derivatives; Methane - chemistry; Methyl axis order parameter; Methyl group; Proteins - analysis; Proteins - chemistry
• ISSN: 1090-7807; 1096-0856
• DOI: 10.1016/j.jmr.2012.02.017

[Display omitted] ► Experiments are presented for separation of individual 1H transitions in methyls. ► Intra-methyl 1H–1H/1H–13C cross-correlations in these transitions are quantified. ► 1H–1H/1H–13C cross-correlations serve as good measures of side-chain ordering. A pair of NMR experiments is developed for separation of individual fast-relaxing transitions in 13CH3 methyl groups of methyl-protonated, highly deuterated proteins, and the measurement of their relaxation rates. Intra-methyl 1H–1H/1H–13C dipole–dipole cross-correlated spin relaxation that differentiates the rates of the fast-relaxing transitions depending on the state of 13C spins, is measured in the selectively [13CH3]-methyl-labeled, deuterated ubiquitin at 10, 27, and 40°C. In contrast with previous observations, the 1H–1H/1H–13C cross-correlated relaxation rates measured from relaxation rates of single-quantum proton transitions serve as good measures of side-chain order even in proteins with global rotational correlation times significantly less than 10ns.