1y4h
From Proteopedia
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Wild type staphopain-staphostatin complex
Overview
Staphostatins are the endogenous, highly specific inhibitors of, staphopains, the major secreted cysteine proteases from Staphylococcus, aureus. We have previously shown that staphostatins A and B are, competitive, active site-directed inhibitors that span the active site, clefts of their target proteases in the same orientation as substrates. We, now report the crystal structure of staphostatin B in complex with, wild-type staphopain B at 1.9 A resolution. In the complex structure, the, catalytic residues are found in exactly the positions that would be, expected for uncomplexed papain-type proteases. There is robust, continuous density for the staphostatin B binding loop and no indication, for cleavage of the peptide bond that comes closest to the active site, cysteine of staphopain B. The carbonyl carbon atom C of this peptide bond, is 4.1 A away from the active site cysteine sulfur Sgamma atom. The, carbonyl oxygen atom O of this peptide bond points away from the putative, oxyanion hole and lies almost on a line from the Sgamma atom to the C, atom. The arrangement is strikingly similar to the "ionmolecule", arrangement for the complex of papain-type enzymes with their substrates, but differs significantly from the arrangement conventionally assumed for, the Michaelis complex of papain-type enzymes with their substrates and, also from the arrangement that is crystallographically observed for, complexes of standard mechanism inhibitors and their target serine, proteases.
About this Structure
1Y4H is a Protein complex structure of sequences from Staphylococcus aureus with CL and SO4 as ligands. Full crystallographic information is available from OCA.
Reference
A comparison of staphostatin B with standard mechanism serine protease inhibitors., Filipek R, Potempa J, Bochtler M, J Biol Chem. 2005 Apr 15;280(15):14669-74. Epub 2005 Jan 11. PMID:15644332
Page seeded by OCA on Wed Nov 21 06:33:42 2007
