An HNCO-based pulse scheme for the measurement of 13Cα-1Hα one-bond dipolar couplings in 15N, 13C labeled proteins

A triple resonance pulse scheme is presented for recording 13C(alpha)-H-1(alpha) one-bond dipolar couplings in N-15, C-13 labeled proteins. HNCO correlation maps are generated where the carbonyl chemical shift is modulated by the C-13(alpha)-H-1(alpha) coupling, With the two doublet components separated into individual data sets. The experiment makes use of recently described methodology whereby the protein of interest is dissolved in a dilute solution of bicelles which orient above a critical temperature, thus permitting measurement of significant couplings (Tjandra and Bar, 1997a). An application to the protein ubiquitin is described.