Understanding the Role of Conformational Dynamics in Protein–Ligand Interactions Using NMR Relaxation Methods

Protein conformational dynamics is a central component of ligand-binding processes because it affects the thermodynamics and the kinetics of binding. The difference in flexibility of the protein between the free and bound states makes a significant contribution to the free energy of ligand binding. In addition, conformational transitions are often necessary to allow binding of a ligand and can determine the kinetics of binding. For these reasons, characterization of protein dynamics is essential to understanding ligand-binding processes. NMR spectroscopy allows protein motions to be characterized over a broad range of time scales with atomic resolution. In this review, we survey NMR spin relaxation methods and discuss their application to the study of ligand-binding processes. Keywords: protein dynamics; conformational entropy; induced fit; conformational selection; extended conformational selection; NMR relaxation