Journal
JOURNAL OF BIOLOGICAL CHEMISTRY
Volume 278, Issue 46, Pages 45763-45769Publisher
AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC
DOI: 10.1074/jbc.M305481200
Keywords
-
Categories
Funding
- NCI NIH HHS [CA89450, CA68485] Funding Source: Medline
- NIEHS NIH HHS [ES00267] Funding Source: Medline
Ask authors/readers for more resources
A variety of drugs inhibit the conversion of arachidonic acid to prostaglandin G(2) by the cyclooxygenase (COX) activity of prostaglandin endoperoxide synthases. Several modes of inhibitor binding in the COX active site have been described including ion pairing of carboxylic acid containing inhibitors with Arg-120 of COX-1 and COX-2 and insertion of arylsulfonamides and sulfones into the COX-2 side pocket. Recent crystallographic evidence suggests that Tyr-385 and Ser-530 chelate polar or negatively charged groups in arachidonic acid and aspirin. We tested the generality of this binding mode by analyzing the action of a series of COX inhibitors against site-directed mutants of COX-2 bearing changes in Arg-120, Tyr-355, Tyr-348, and Ser-530. Interestingly, diclofenac inhibition was unaffected by the mutation of Arg-120 to alanine but was dramatically attenuated by the S530A mutation. Determination of the crystal structure of a complex of diclofenac with murine COX-2 demonstrates that diclofenac binds to COX-2 in an inverted conformation with its carboxylate group hydrogen-bonded to Tyr-385 and Ser-530. This finding represents the first experimental demonstration that the carboxylate group of an acidic non-steroidal anti-inflammatory drug can bind to a COX enzyme in an orientation that precludes the formation of a salt bridge with Arg-120. Mutagenesis experiments suggest Ser-530 is also important in time-dependent inhibition by nimesulide and piroxicam.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available