A simple and sensitive experiment for measurement of JCC couplings between backbone carbonyl and methyl carbons in isotopically enriched proteins.
A simple 2D difference experiment is described that allows quantitative measurement of 13C-13C J couplings between backbone carbonyl and side-chain carbons. Precise 3JCC values were measured from data recorded in just 2 h for a 1-mM solution of the 20-kD complex between the protein calmodulin and a 26-residue synthetic peptide. The J couplings aid in determining the chi 1 angles of valine, isoleucine and threonine residues, and in making stereospecific assignments of the Val C gamma methyl groups. Error analysis indicates that the uncertainty in the derived J couplings is generally less than ca. 0.3 Hz.
Grzesiek
S
S
Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892.
Vuister
G W
GW
Bax
A
A
D000596:Amino Acids / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D015394:Molecular Structure; D011506:Proteins / Q000737:chemistry*; D012680:Sensitivity and Specificity
D000596:Amino Acids; D011506:Proteins