Oxicams Bind in a Novel Mode to the Cyclooxygenase Active Site via a Two-water-mediated H-bonding Network

Abstract

Background:The oxicams are anti-inflammatory drugs targeting the cyclooxygenase enzymes. Results: Crystal complexes of mCOX-2⅐isoxicam, mCOX-2⅐meloxicam, and oCOX-1⅐meloxicam are solved. Conclusion: Oxicams bind to the cyclooxygenase active sites in a novel mode. Significance: The first structural description of cyclooxygenase-oxicam complexes reveal a new binding pocket of inhibitors to cyclooxygenases.

13-Methylarachidonic Acid Is a Positive Allosteric Modulator of Endocannabinoid Oxygenation by Cyclooxygenase

“…To remove traces of heme from mCOX-2, 5 mM glutathione and 0.05% deoxycholate (sodium salt) were added to the size exclusion buffer. Site-directed mutagenesis to generate COX-2 active site mutants was performed as described previously (30).…”

“…Crystallization, Data Collection, Structure Determination, and Refinement-Crystallization of mCOX-2 was carried out as described previously with modest modification (30). mCOX-2 was reconstituted with a 2-fold molar excess of Co 3ϩ -protoprophyrin IX.…”

Action at a Distance

“…Crystallization of mCOX-2 and Mutants-Crystallization was performed as previously described with modest modification (17,18). Limited trypsin digestion has been used in the successful crystallization of COX-2 to remove the disordered C-terminal tail, which is not resolved in most crystal structures (15).…”

“…The reaction was quenched by the addition of ice-cold ethyl acetate containing 0.5% (v/v) acetic acid and 300 pM concentrations of internal standards (PGE 2 -d 4 ). The solution was then vigorously mixed and cooled on ice, and the separated organic fraction was dried under nitrogen for the analysis of PGs by LC-MS/MS (17,18). The kinetic data were fit using Prism Software to the MichaelisMenten kinetic model.…”

Design, Synthesis, and Anti-inflammatory Activity of Novel Quinazolines

“…The crystallographic enzyme ligand complex with SC-558 was obtained from the RCSB protein data bank (PDB entry ICX 2 ) 15,16 .…”