Structural analysis of non-native states of proteins by NMR methods

Established NMR methods are increasingly being applied to the non-native states of proteins. For small denatured proteins, full assignment of proton, ¹⁵N and ¹³C resonances is often straightforward. Sensitive methods exist for detecting fractionally populated α helices and β strands, but defining transient interactions among side chains is proving more problematic. The non-native states of several small proteins are being intensively investigated to address a number of questions about protein folding.