Experiments and strategies for the assignment of fully 13C/15N-labelled polypeptides by solid state NMR

High-resolution heteronuclear NMR correlation experiments and strategies are proposed for the assignment of fully C-13/N-15-labelled polypeptides in the solid state. By the combination of intra-residue and inter-residue C-13-N-15 correlation experiments with C-13-C-13 spin-diffusion studies, it becomes feasible to partially assign backbone and side-chain resonances in solid proteins. The performance of sequences using N-15 instead of C-13 detection is evaluated regarding sensitivity and resolution for a labelled dipeptide (L-Val-L-Phe). The techniques are used for a partial assignment of the N-15 and C-13 resonances in human ubiquitin.