Characterizing semilocal motions in proteins by NMR relaxation studies

The understanding of protein function is incomplete without the study of protein dynamics. NMR spectroscopy is valuable for probing nanosecond and picosecond dynamics via relaxation studies. The use of (15)N relaxation to study backbone dynamics has become virtually standard. Here, we propose to measure the relaxation of additional nuclei on each peptide plane allowing for the observation of anisotropic local motions. This allows the nature of local motions to be characterized in proteins. As an example, semilocal rotational motion was detected for part of a helix of the protein Escherichia coli flavodoxin.