NMR probes of molecular dynamics: Overview and comparison with other techniques

NMR spin relaxation spectroscopy is a powerful approach for characterizing intramolecular and overall rotational motions in proteins. This review describes experimental methods for measuring laboratory frame spin relaxation rate constants by high-resolution solution-state NMR spectroscopy, together with theoretical approaches for interpreting spin relaxation data in order to quantify protein conformational dynamics on picosecond-nanosecond time scales. Recent applications of these techniques to proteins are surveyed, and investigations of the contribution of conformational chain entropy to protein function are highlighted. Insights into the dynamical properties of proteins obtained from NMR spin relaxation spectroscopy are compared with results derived from other experimental and theoretical techniques.