文摘
Structure-based drug design relies on static protein structures despite significant evidence for the need to include protein dynamics as a serious consideration. In practice, dynamic motions are neglected because they are not understood well enough to model, a situation resulting from a lack of explicit experimental examples of dynamic receptor鈭抣igand complexes. Here, we report high-resolution details of pronounced 1 ms time scale motions of a receptor鈭抯mall molecule complex using a combination of NMR and X-ray crystallography. Large conformational dynamics in Escherichia coli dihydrofolate reductase are driven by internal switching motions of the drug-like, nanomolar-affinity inhibitor. Carr鈭扨urcell鈭扢eiboom鈭扜ill relaxation dispersion experiments and NOEs revealed the crystal structure to contain critical elements of the high energy protein鈭抣igand conformation. The availability of accurate, structurally resolved dynamics in a protein鈭抣igand complex should serve as a valuable benchmark for modeling dynamics in other receptor鈭抣igand complexes and prediction of binding affinities.