3er5
From Proteopedia
THE ACTIVE SITE OF ASPARTIC PROTEINASES
Structural highlights
Function[ANGT_BOVIN] Essential component of the renin-angiotensin system (RAS), a potent regulator of blood pressure, body fluid and electrolyte homeostasis (By similarity). Angiotensin-2: acts directly on vascular smooth muscle as a potent vasoconstrictor, affects cardiac contractility and heart rate through its action on the sympathetic nervous system, and alters renal sodium and water absorption through its ability to stimulate the zona glomerulosa cells of the adrenal cortex to synthesize and secrete aldosterone (By similarity). Angiotensin-3: stimulates aldosterone release (By similarity). Angiotensin 1-7: is a ligand for the G-protein coupled receptor MAS1 (By similarity). Has vasodilator and antidiuretic effects (By similarity). Has an antithrombotic effect that involves MAS1-mediated release of nitric oxide from platelets (By similarity). Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedH-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). 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[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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