FIGURE 1.

Chemical structures of NSAIDs and crystal structures of flurbiprofen and diclofenac bound in mCOX-2 active site. A, chemical structures of naproxen, flurbiprofen, diclofenac, and indomethacin. The structures of flurbiprofen (Protein Data Bank entry 3PGH; inhibitor carbon atoms colored gold) (B) and diclofenac (Protein Data Bank entry 1PXX) (C) bound at the COX-2 active site show the opposing binding modes that position their acidic groups either coordinated to the constriction residues Arg-120 and Tyr-355 at the base of the active site or to the catalytic Tyr-385 as well as Ser-530 at the top of the pocket.