Accurate measurement of methyl 13C chemical shifts by solid-state NMR for the determination of protein side chain conformation: the influenza a M2 transmembrane peptide as an example.

ABSTRACT: The use of side chain methyl (13)C chemical shifts for the determination of the rotameric conformation of Val and Leu residues in proteins by solid-state NMR spectroscopy is described. Examination of the solution NMR stereospecifically assigned methyl groups shows significant correlation between the difference in the two methyl carbons' chemical shifts and the side chain conformation. It is found that alpha-helical and beta-sheet backbones cause different side chain methyl chemical shift trends. In alpha-helical Leu's, a relatively large absolute methyl (13)C shift difference of 2.89 ppm is found for the most populated mt rotamer (chi(1) = -60 degrees, chi(2) = 180 degrees), while a much smaller value of 0.73 ppm is found for the next populated tp rotamer (chi(1) = 180 degrees, chi(2) = 60

SUBMITTER: Hong M 

PROVIDER: S-EPMC4082989 | biostudies-literature | 2009 Jun

REPOSITORIES: biostudies-literature