Experiments and strategies for the assignment of fully13 C/15N-labelled polypeptides by solid state NMR

High-resolution heteronuclear NMR correlation experiments and strategies are proposed for the assignment of fully¹³ C/¹⁵N-labelled polypeptides in the solid state. By the combination of intra-residue and inter-residue¹³ C-¹⁵N correlation experiments with¹³ C-¹³C spin-diffusion studies, it becomes feasible to partially assign backbone and side-chain resonances in solid proteins. The performance of sequences using ¹⁵N instead of¹³ C 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 ¹⁵N and ¹³C resonances in human ubiquitin.