O-acetylsalicylhydroxamic acid, a novel acetylating inhibitor of prostaglandin H2 synthase: structural and functional characterization of enzyme-inhibitor interactions.Loll, P.J., Sharkey, C.T., O'Connor, S.J., Dooley, C.M., O'Brien, E., Devocelle, M., Nolan, K.B., Selinsky, B.S., Fitzgerald, D.J.
(2001) Mol.Pharmacol. 60: 1407-1413
- PubMed: 11723249
- PubMed Abstract:
Aspirin is unique among clinically used nonsteroidal antiinflammatory drugs in that it irreversibly inactivates prostaglandin (PG) H2 synthase (PGHS) via acetylation of an active-site serine residue. We report the synthesis and characterization of a ...
Aspirin is unique among clinically used nonsteroidal antiinflammatory drugs in that it irreversibly inactivates prostaglandin (PG) H2 synthase (PGHS) via acetylation of an active-site serine residue. We report the synthesis and characterization of a novel acetylating agent, O-acetylsalicylhydroxamic acid (AcSHA), which inhibits PGE2 synthesis in vivo and blocks the cyclooxygenase activity of PGHS in vitro. AcSHA requires the presence of the active-site residue Ser-529 to be active against human PGHS-1; the S529A mutant is resistant to inactivation by the inhibitor. Analysis of PGHS inactivation by AcSHA, coupled with the X-ray crystal structure of the complex of ovine PGHS-1 with AcSHA, confirms that the inhibitor elicits its effects via acetylation of Ser-529 in the cyclooxygenase active site. The crystal structure reveals an intact inhibitor molecule bound in the enzyme's cyclooxygenase active-site channel, hydrogen bonding with Arg-119 of the enzyme. The structure-activity profile of AcSHA can be rationalized in terms of the crystal structure of the enzyme-ligand complex. AcSHA may prove useful as a lead compound to facilitate the development of new acetylating inhibitors.
Department of Pharmacology, University of Pennsylvania School of Medicine, Philadelphia, PA, USA.