1F32
CRYSTAL STRUCTURE OF ASCARIS PEPSIN INHIBITOR-3
Summary for 1F32
| Entry DOI | 10.2210/pdb1f32/pdb |
| Related | 1F34 |
| Descriptor | MAJOR PEPSIN INHIBITOR PI-3 (2 entities in total) |
| Functional Keywords | proteinase inhibitor, hydrolase inhibitor |
| Biological source | Ascaris suum (pig roundworm) |
| Cellular location | Secreted: P19400 |
| Total number of polymer chains | 1 |
| Total formula weight | 16411.69 |
| Authors | Ng, K.K.,Petersen, J.F.,Cherney, M.M.,Garen, C.,James, M.N. (deposition date: 2000-05-31, release date: 2001-02-01, Last modification date: 2024-11-13) |
| Primary citation | Ng, K.K.,Petersen, J.F.,Cherney, M.M.,Garen, C.,Zalatoris, J.J.,Rao-Naik, C.,Dunn, B.M.,Martzen, M.R.,Peanasky, R.J.,James, M.N. Structural basis for the inhibition of porcine pepsin by Ascaris pepsin inhibitor-3. Nat.Struct.Biol., 7:653-657, 2000 Cited by PubMed Abstract: 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. PubMed: 10932249DOI: 10.1038/77950 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (1.75 Å) |
Structure validation
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