Solution-state NMR has been widely applied to determine the threedimensional
structure, dynamics, and molecular interactions of proteins. The designs of
experiments used in protein NMR differ from those used for small-molecule NMR,
primarily because the information available prior to an experiment, such as molecular
mass and knowledge of the primary structure, is unique for proteins compared to small
molecules. In this review article, protein NMR for structural biology is introduced with
comparisons to small-molecule NMR, such as descriptions of labeling strategies and the
effects of molecular dynamics on relaxation. Next, applications for protein NMR are
reviewed, especially practical aspects for protein-observed ligand-protein interaction
studies. Overall, the following topics are described: (1) characteristics of protein NMR,
(2) methods to detect protein-ligand interactions by NMR, and (3) practical aspects of
carrying out protein-observed inhibitor-protein interaction studies.
Keywords: Drug, inhibitor, interaction, NMR, protein, relaxation, structure.