3er5
From Proteopedia
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'''THE ACTIVE SITE OF ASPARTIC PROTEINASES''' | '''THE ACTIVE SITE OF ASPARTIC PROTEINASES''' | ||
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[[Category: Szelke, M.]] | [[Category: Szelke, M.]] | ||
[[Category: Veerapandian, B.]] | [[Category: Veerapandian, B.]] | ||
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Revision as of 19:01, 4 May 2008
THE ACTIVE SITE OF ASPARTIC PROTEINASES
Overview
H-189, a synthetic human renin inhibitor, and pepstatin A, a naturally occurring inhibitor of aspartic proteinases, have been co-crystallized with the fungal aspartic proteinase endothiapepsin (EC 3.4.23.6). H-189 [Pro-His-Pro-Phe-His-Sta-(statyl)-Val-Ile-His-Lys] is an analogue of human angiotensinogen. Pepstatin A [Iva(isovaleryl)-Val-Val-Sta-Ala-Sta] is a blocked pentapeptide which inhibits many aspartic proteinases. The structures of the complexes have been determined by X-ray diffraction and refined to crystallographic R-factors of 0.15 and 0.16 at resolutions of 0.18 nm (1.8 A) and 0.2 nm (2.0 A) respectively. H-189 is in an extended conformation, in which the statine residue is a dipeptide analogue of P1 and P'1 as indicated by the conformation and network of contacts and hydrogen bonds. Pepstatin A has an extended conformation to the P'2 alanine residue, but the leucyl side chain of the terminal statine residue binds back into the S'1 subsite, and an inverse gamma-turn occurs between P'1 and P'3. The hydroxy moiety of the statine at P1 in both complexes displaces the solvent molecule that hydrogen-bonds with the catalytic aspartate residues (32 and 215) in the native enzyme. Solvent molecules originally present in the native structure at the active site are displaced on inhibitor binding (12 when pepstatin A binds; 16 when H-189 binds).
About this Structure
3ER5 is a Protein complex structure of sequences from Cryphonectria parasitica. Full crystallographic information is available from OCA.
Reference
X-ray-crystallographic studies of complexes of pepstatin A and a statine-containing human renin inhibitor with endothiapepsin., Bailey D, Cooper JB, Veerapandian B, Blundell TL, Atrash B, Jones DM, Szelke M, Biochem J. 1993 Jan 15;289 ( Pt 2):363-71. PMID:8424781 Page seeded by OCA on Sun May 4 22:00:59 2008
