3OLT

X-ray crystal structure of arachidonic acid bound to the cyclooxygenase channel of R513H murine COX-2

Summary for 3OLT

• Entry DOI: 10.2210/pdb3olt/pdb
• Related: 1DIY 3HS5 3HS6 3HS7 3KRK 3MDL 3OLU
• Descriptor: Prostaglandin G/H synthase 2, 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose, alpha-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose, ... (9 entities in total)
• Functional Keywords: monotopic membrane protein, oxidoreductase, n-glycosylation, membrane
• Biological source: Mus musculus (mouse)
• Total number of polymer chains: 2
• Total formula weight: 141530.58

Authors

Vecchio, A.J.,Malkowski, M.G. (deposition date: 2010-08-26, release date: 2011-04-13, Last modification date: 2024-12-25)

Primary citation

Vecchio, A.J.,Malkowski, M.G.
The structural basis of endocannabinoid oxygenation by cyclooxygenase-2.
J.Biol.Chem., 286:20736-20745, 2011

PubMed Abstract: The cyclooxygenases (COX-1 and COX-2) oxygenate arachidonic acid (AA) in the committed step of prostaglandin biogenesis. Substitutions of I434V, H513R, and I523V constitute the only differences in residues lining the cyclooxygenase channel between COX-1 and COX-2. These changes create a hydrophobic pocket in COX-2, with Arg-513 located at the base of the pocket, which has been exploited in the design of COX-2-selective inhibitors. Previous studies have shown that COX-2, but not COX-1, can oxygenate endocannabinoid substrates, including 2-arachidonoyl glycerol (2-AG). To investigate the isoform-specific structural basis of endocannabinoid binding to COX-2, we determined the crystal structure of the 2-AG isomer 1-arachidonoyl glycerol (1-AG) in complex with wild type and R513H murine (mu) COX-2 to 2.2 and 2.35 Å, respectively, and R513H muCOX-2 in complex with AA to 2.45 Å resolution. The 2,3-dihydroxypropyl moiety of 1-AG binds near the opening of the cyclooxygenase channel in the space vacated by the movement of the Leu-531 side chain, validating our previous hypothesis implicating the flexibility of the Leu-531 side chain as a determinant for the ability of COX-2 to oxygenate endocannabinoid substrates. Functional analyses carried out to compliment our structural findings indicated that Y355F and R513H muCOX-2 constructs had no effect on the oxygenation of 1-AG and 2-AG, whereas substitutions that resulted in a shortened side chain for Leu-531 had only modest effects. Both AA and 1-AG bind to R513H muCOX-2 in conformations similar to those observed in the co-crystal structures of these substrates with wild type enzyme.

PubMed: 21489986
DOI: 10.1074/jbc.M111.230367

Experimental method

X-RAY DIFFRACTION (2.45 Å)