title: Structural insights into the stereochemistry of the cyclooxygenase reaction.
abstract: Cyclooxygenases are bifunctional enzymes that catalyse the first committed step in the synthesis of prostaglandins, thromboxanes and other eicosanoids. The two known cyclooxygenases isoforms share a high degree of amino-acid sequence similarity, structural topology and an identical catalytic mechanism. Cyclooxygenase enzymes catalyse two sequential reactions in spatially distinct, but mechanistically coupled active sites. The initial cyclooxygenase reaction converts arachidonic acid (which is achiral) to prostaglandin G2 (which has five chiral centres). The subsequent peroxidase reaction reduces prostaglandin G2 to prostaglandin H2. Here we report the co-crystal structures of murine apo-cyclooxygenase-2 in complex with arachidonic acid and prostaglandin. These structures suggest the molecular basis for the stereospecificity of prostaglandin G2 synthesis.
authors.affiliation: Searle Discovery Research, Monsanto Company, St Louis, Missouri 63198, USA.
authors.forename: J R
authors.initials: JR
authors.lastname: Kiefer
authors.forename: J L
authors.initials: JL
authors.lastname: Pawlitz
authors.forename: K T
authors.initials: KT
authors.lastname: Moreland
authors.forename: R A
authors.initials: RA
authors.lastname: Stegeman
authors.forename: W F
authors.initials: WF
authors.lastname: Hood
authors.forename: J K
authors.initials: JK
authors.lastname: Gierse
authors.forename: A M
authors.initials: AM
authors.lastname: Stevens
authors.forename: D C
authors.initials: DC
authors.lastname: Goodwin
authors.forename: S W
authors.initials: SW
authors.lastname: Rowlinson
authors.forename: L J
authors.initials: LJ
authors.lastname: Marnett
authors.forename: W C
authors.initials: WC
authors.lastname: Stallings
authors.forename: R G
authors.initials: RG
authors.lastname: Kurumbail
mesh_terms: D000818:Animals; D001051:Apoenzymes / Q000737:chemistry / Q000378:metabolism; D016718:Arachidonic Acid / Q000737:chemistry* / Q000378:metabolism; D001665:Binding Sites; D018360:Crystallography, X-Ray; D051546:Cyclooxygenase 2; D007527:Isoenzymes / Q000737:chemistry* / Q000378:metabolism; D051379:Mice; D008958:Models, Molecular; D044262:Prostaglandin H2; D011451:Prostaglandin-Endoperoxide Synthases / Q000737:chemistry* / Q000378:metabolism; D011463:Prostaglandins H / Q000737:chemistry* / Q000378:metabolism; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D013237:Stereoisomerism
chemical_list: D001051:Apoenzymes; D007527:Isoenzymes; D011463:Prostaglandins H; D011994:Recombinant Proteins; D016718:Arachidonic Acid; D044262:Prostaglandin H2; D051546:Cyclooxygenase 2; D011451:Prostaglandin-Endoperoxide Synthases