title: Observation and relaxation properties of individual fast-relaxing proton transitions in [¹³CH₃]-methyl-labeled, deuterated proteins.
abstract: A pair of NMR experiments is developed for separation of individual fast-relaxing transitions in (13)CH(3) methyl groups of methyl-protonated, highly deuterated proteins, and the measurement of their relaxation rates. Intra-methyl (1)H-(1)H/(1)H-(13)C dipole-dipole cross-correlated spin relaxation that differentiates the rates of the fast-relaxing transitions depending on the state of (13)C spins, is measured in the selectively [(13)CH(3)]-methyl-labeled, deuterated ubiquitin at 10, 27, and 40°C. In contrast with previous observations, the (1)H-(1)H/(1)H-(13)C 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 10 ns.
authors.affiliation: Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, United States.
authors.forename: Hechao
authors.initials: H
authors.lastname: Sun
authors.forename: Vitali
authors.initials: V
authors.lastname: Tugarinov
mesh_terms: D003903:Deuterium / Q000737:chemistry*; D041961:Deuterium Exchange Measurement / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008697:Methane / Q000031:analogs & derivatives* / Q000737:chemistry; D011506:Proteins / Q000032:analysis* / Q000737:chemistry*
chemical_list: D011506:Proteins; C051224:methyl radical; D003903:Deuterium; D008697:Methane