title: Crystal structure of a lipoxygenase in complex with substrate: the arachidonic acid-binding site of 8R-lipoxygenase.
abstract: Lipoxygenases (LOX) play critical roles in mammalian biology in the generation of potent lipid mediators of the inflammatory response; consequently, they are targets for the development of isoform-specific inhibitors. The regio- and stereo-specificity of the oxygenation of polyunsaturated fatty acids by the enzymes is understood in terms of the chemistry, but structural observation of the enzyme-substrate interactions is lacking. Although several LOX crystal structures are available, heretofore the rapid oxygenation of bound substrate has precluded capture of the enzyme-substrate complex, leaving a gap between chemical and structural insights. In this report, we describe the 2.0 Å resolution structure of 8R-LOX in complex with arachidonic acid obtained under anaerobic conditions. Subtle rearrangements, primarily in the side chains of three amino acids, allow binding of arachidonic acid in a catalytically competent conformation. Accompanying experimental work supports a model in which both substrate tethering and cavity depth contribute to positioning the appropriate carbon at the catalytic machinery.
authors.affiliation: Department of Chemistry and Chemical Biology, Cornell University, Northeastern Collaborative Access Team, Argonne National Laboratory, Argonne, Illinois 60439, and.
authors.forename: David B
authors.initials: DB
authors.lastname: Neau
authors.affiliation: Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana 70803.
authors.forename: Gunes
authors.initials: G
authors.lastname: Bender
authors.affiliation: Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232.
authors.forename: William E
authors.initials: WE
authors.lastname: Boeglin
authors.affiliation: Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana 70803.
authors.forename: Sue G
authors.initials: SG
authors.lastname: Bartlett
authors.affiliation: Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232.
authors.forename: Alan R
authors.initials: AR
authors.lastname: Brash
authors.affiliation: Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana 70803,. Electronic address: newcomer@lsu.edu.
authors.forename: Marcia E
authors.initials: ME
authors.lastname: Newcomer
mesh_terms: D000818:Animals; D001091:Arachidonate Lipoxygenases / Q000737:chemistry*; D016718:Arachidonic Acid / Q000737:chemistry; D001665:Binding Sites; D002384:Catalysis; D018360:Crystallography, X-Ray; D006801:Humans; D007249:Inflammation; D007501:Iron / Q000737:chemistry; D008055:Lipids / Q000737:chemistry; D008958:Models, Molecular; D016296:Mutagenesis; D009154:Mutation; D010100:Oxygen / Q000737:chemistry; D011485:Protein Binding; D011487:Protein Conformation; D011817:Rabbits; D013552:Swine
chemical_list: D008055:Lipids; D016718:Arachidonic Acid; D007501:Iron; D001091:Arachidonate Lipoxygenases; C054192:arachidonate 8-lipoxygenase; D010100:Oxygen
keywords: Arachidonic Acid (AA) (ARA); Eicosanoid Biosynthesis; Lipid Signaling; Lipoxygenase Pathway; Protein Structure; X-ray Crystallography