This research plan involves the investigation of a closely related set of variants of the enzyme Staphylococcal nuclease (SNase) in complexes with inhibitors and substrates. These studies are aimed at determining the details of the structural and dynamical correlates of the enzymatic reaction. These studies will utilize a new type of SNase, SNase, n which the solvent accessible and disordered loop has been deleted. Preliminary studies suggest that (i) the deletion of the loop does not have large structural consequences; (ii) by random mutation of residues 50 & 51 a series of proteins can be generated which have continuum of structures and activities; (iii) the residue at position 43 can be varied in conjunction with random mutation at positions 50 & 51 to investigate the structure-function correlates of basic catalysis; (iv) the comparison of the inhibitor and substrate binding of loop containing and sNase could offer important information about the details of active site interactions and (v) the comparison of the flexibility of loop containing and SNAse may offer information about the role of active site flexibility on the catalytic reaction. the major technique to be used in these studies in NMR.
