Sensitivity-enhanced E.COSY-type HSQC experiments for accurate measurements of one-bond 15N-1HN and 15N-13C′ and two-bond 13C′-1HN residual dipolar couplings in proteins

Novel E.COSY-type HSQC experiments are presented for the accurate measurement of one-bond N-15-H-1(N) and N-15-C-13' and two-bond C-13'-H-1(N) residual dipolar couplings in proteins. Compared with existing experiments, the (delta,J)-E.COSY experiments described here are composed of fewer pulses and the resulting spectra exhibit 1.4 times the sensitivity of coupled HSQC spectra. Since residual dipolar couplings play increasingly important roles in structural NMR, the proposed methods should find wide spread application for structure determination of proteins and other biological macromolecules. (C) 2002 Elsevier Science (USA). All rights reserved.