Solution structure of the first SH3 domain of human vinexin and its interaction with vinculin peptides.

Solution structure of the first Src homology (SH) 3 domain of human vinexin (V{sub S}H3{sub 1}) was determined using nuclear magnetic resonance (NMR) method and revealed that it was a canonical SH3 domain, which has a typical {beta}-{beta}-{beta}-{beta}-{alpha}-{beta} fold. Using chemical shift perturbation and surface plasmon resonance experiments, we studied the binding properties of the SH3 domain with two different peptides from vinculin hinge regions: P856 and P868. The observations illustrated slightly different affinities of the two peptides binding to V{sub S}H3{sub 1}. The interaction between P868 and V{sub S}H3{sub 1} belonged to intermediate exchange with a modest binding affinity, while the interaction between P856 and V{sub S}H3{sub 1} had a low binding affinity. The structure and ligand-binding interface of V{sub S}H3{sub 1} provide a structural basis for the further functional study of this important molecule.