title: Structural insights into xenobiotic and inhibitor binding to human aldehyde oxidase.
abstract: Aldehyde oxidase (AOX) is a xanthine oxidase (XO)-related enzyme with emerging importance due to its role in the metabolism of drugs and xenobiotics. We report the first crystal structures of human AOX1, substrate free (2.6-Å resolution) and in complex with the substrate phthalazine and the inhibitor thioridazine (2.7-Å resolution). Analysis of the protein active site combined with steady-state kinetic studies highlight the unique features, including binding and substrate orientation at the active site, that characterize human AOX1 as an important drug-metabolizing enzyme. Structural analysis of the complex with the noncompetitive inhibitor thioridazine revealed a new, unexpected and fully occupied inhibitor-binding site that is structurally conserved among mammalian AOXs and XO. The new structural insights into the catalytic and inhibition mechanisms of human AOX that we now report will be of great value for the rational analysis of clinical drug interactions involving inhibition of AOX1 and for the prediction and design of AOX-stable putative drugs.
authors: Research Unit on Applied Molecular Biosciences-Rede de Química e Tecnologia (UCIBIO-REQUIMTE), Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal.
authors: Catarina
authors: C
authors: Coelho
authors: Department of Molecular Enzymology, Institute of Biochemistry and Biology, University of Potsdam, Potsdam, Germany.
authors: Alessandro
authors: A
authors: Foti
authors: Department of Molecular Enzymology, Institute of Biochemistry and Biology, University of Potsdam, Potsdam, Germany.
authors: Tobias
authors: T
authors: Hartmann
authors: Research Unit on Applied Molecular Biosciences-Rede de Química e Tecnologia (UCIBIO-REQUIMTE), Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal.
authors: Teresa
authors: T
authors: Santos-Silva
authors: Department of Molecular Enzymology, Institute of Biochemistry and Biology, University of Potsdam, Potsdam, Germany.
authors: Silke
authors: S
authors: Leimkühler
authors: Research Unit on Applied Molecular Biosciences-Rede de Química e Tecnologia (UCIBIO-REQUIMTE), Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal.
authors: Maria João
authors: MJ
authors: Romão
mesh_terms: D042931:Aldehyde Oxidase / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D000445:Aldehyde Oxidoreductases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D000818:Animals; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics; D006801:Humans; D051379:Mice; D008958:Models, Molecular; D011485:Protein Binding; D011487:Protein Conformation; D013045:Species Specificity; D013379:Substrate Specificity; D015262:Xenobiotics / Q000737:chemistry / Q000378:metabolism*
chemical_list: D004791:Enzyme Inhibitors; D015262:Xenobiotics; D000445:Aldehyde Oxidoreductases; C443116:Aox3 protein, mouse; C526436:AOX1 protein, human; D042931:Aldehyde Oxidase