Transverse relaxation optimised spin-state selective NMR experiments for measurement of residual dipolar couplings

Three transverse relaxation optimised NMR experiments (TROSY) for the measu rement of scalar and dipolar couplings suitable for proteins dissolved in a queous iso- and anisotropic solutions are described. The triple-spin-state- selective experiments yield couplings between H-1(N)-C-13(alpha), N-15-C-13 (alpha), H-1(N)-C-13(i-1)alpha, N-15-C-13(i-1)alpha, H-1(N)-C-13(i-1)', N-1 5-C-13(i-1)', and C-13(i-1)'-C-13(i-1)alpha without introducing nonessentia l spectral crowding compared with an ordinary two-dimensional N-15-H-1 corr elation spectrum and without requiring explicit knowledge of carbon assignm ents. This set of alpha/beta-J-TROSY experiments is most useful for perdeut erated proteins in studies of structure-activity relationships by NMR to ob serve, in addition to epitopes for ligands, also conformational changes ind uced by binding of ligands.