title: Selective detection of ¹³CHD₂ signals from a mixture of ¹³CH₃/¹³CH₂D/¹³CHD₂ methyl isotopomers in proteins.
abstract: In NMR spectra of partially deuterated proteins methyl correlations are commonly observed as a combination of signals from ¹³CH₃, ¹³CH₂D and ¹³CHD₂ isotopomers. In a number of NMR applications, methyl groups of the ¹³CHD₂ variety are targeted because of their AX-like character and concomitant simplification of the involved relaxation mechanisms. Although complete elimination of signals from ¹³CH₂D methyl groups can be easily achieved in such applications, if the magnetization is not transferred through deuterium nuclei, efficient suppression of usually stronger ¹³CH₃ peaks is more problematic. A pair of simple pulse-scheme elements are presented that achieve almost complete suppression of ¹³CH₃ signals in the mixtures of ¹³CH₃/¹³CH₂D/¹³CHD₂ methyl isotopomers of small proteins at the expense of a moderate (∼20-to-40%) reduction in intensities of the targeted ¹³CHD₂ groups. The approaches described are based purely on scalar coupling (¹J(CH)) evolution properties of different ¹³C and ¹H transitions within ¹³CH₃ spin-systems and are superior to magnetization transfer through deuterons with respect to sensitivity of the detected ¹³CHD₂ methyl signals.
authors.affiliation: Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, United States.
authors.forename: Xinli
authors.initials: X
authors.lastname: Liao
authors.forename: Vitali
authors.initials: V
authors.lastname: Tugarinov
mesh_terms: D000465:Algorithms; D045424:Complex Mixtures / Q000737:chemistry*; D041961:Deuterium Exchange Measurement / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008745:Methylation; D010449:Peptide Mapping; D011506:Proteins / Q000737:chemistry*
chemical_list: D045424:Complex Mixtures; D011506:Proteins