1f32
From Proteopedia
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CRYSTAL STRUCTURE OF ASCARIS PEPSIN INHIBITOR-3
Overview
The three-dimensional structures of pepsin inhibitor-3 (PI-3) from Ascaris, suum and of the complex between PI-3 and porcine pepsin at 1. 75 A and, 2.45 A resolution, respectively, have revealed the mechanism of aspartic, protease inhibition by this unique inhibitor. PI-3 has a new fold, consisting of two domains, each comprising an antiparallel beta-sheet, flanked by an alpha-helix. In the enzyme-inhibitor complex, the N-terminal, beta-strand of PI-3 pairs with one strand of the 'active site flap', (residues 70-82) of pepsin, thus forming an eight-stranded beta-sheet that, spans the two proteins. PI-3 has a novel mode of inhibition, using its, N-terminal residues to occupy and therefore block the first three binding, pockets in pepsin for substrate residues C-terminal to the scissile bond, (S1'-S3'). The molecular structure of the pepsin-PI-3 complex suggests new, avenues for the rational design of proteinaceous aspartic proteinase, inhibitors.
About this Structure
1F32 is a Single protein structure of sequence from Ascaris suum. Full crystallographic information is available from OCA.
Reference
Structural basis for the inhibition of porcine pepsin by Ascaris pepsin inhibitor-3., Ng KK, Petersen JF, Cherney MM, Garen C, Zalatoris JJ, Rao-Naik C, Dunn BM, Martzen MR, Peanasky RJ, James MN, Nat Struct Biol. 2000 Aug;7(8):653-7. PMID:10932249
Page seeded by OCA on Tue Nov 20 14:33:55 2007
