Homonuclear decoupled 13C chemical shift anisotropy in 13C doubly labeled peptides by selective-pulse solid-state NMR

We describe a new experiment for measuring homonuclear-decoupled anisotropic chemical shift patterns in doubly C-13-labeled compounds under magic-angle spinning. The experiment combines a pair of selective and non-selective 180degrees pulses to suppress the C-13-C-13 scalar and dipolar interactions. This is combined with the recently developed SUPER technique to recouple the chemical shift anisotropy. Demonstrations on (13)Calpha and (CO)-C-13-labeled amino acids and peptides show that accurate chemical shift powder patterns can be obtained. This permits the use of chemical shift anisotropy for conformational studies of suitably extensively C-13-labeled peptides and proteins. (C) 2003 Elsevier Science (USA). All rights reserved.