Protein dynamics.

Modern NMR has revitalized the study of protein dynamics. Multidimensional spectra and the heteronuclear spectroscopy allow a substantial gain in resolution. Dynamics can be analyzed at individual sites and data on segmental and sequence-dependent flexibility are accumulating. This review summarizes the wide variety of NMR approaches for observing internal motions, including the folding processes, and the attempts to correlate dynamics to the biological activity of proteins. The implications of mobility on structure determination by NMR is also discussed.