title: Structural and biochemical characterization of a quinol binding site of Escherichia coli nitrate reductase A.
abstract: The crystal structure of Escherichia coli nitrate reductase A (NarGHI) in complex with pentachlorophenol has been determined to 2.0 A of resolution. We have shown that pentachlorophenol is a potent inhibitor of quinol:nitrate oxidoreductase activity and that it also perturbs the EPR spectrum of one of the hemes located in the membrane anchoring subunit (NarI). This new structural information together with site-directed mutagenesis data, biochemical analyses, and molecular modeling provide the first molecular characterization of a quinol binding and oxidation site (Q-site) in NarGHI. A possible proton conduction pathway linked to electron transfer reactions has also been defined, providing fundamental atomic details of ubiquinol oxidation by NarGHI at the bacterial membrane.
authors.affiliation: Department of Biochemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada.
authors.forename: Michela G
authors.initials: MG
authors.lastname: Bertero
authors.forename: Richard A
authors.initials: RA
authors.lastname: Rothery
authors.forename: Nasim
authors.initials: N
authors.lastname: Boroumand
authors.forename: Monica
authors.initials: M
authors.lastname: Palak
authors.forename: Francis
authors.initials: F
authors.lastname: Blasco
authors.forename: Nicolas
authors.initials: N
authors.lastname: Ginet
authors.forename: Joel H
authors.initials: JH
authors.lastname: Weiner
authors.forename: Natalie C J
authors.initials: NC
authors.lastname: Strynadka
mesh_terms: D001665:Binding Sites; D002462:Cell Membrane / Q000378:metabolism; D018360:Crystallography, X-Ray; D004305:Dose-Response Relationship, Drug; D004578:Electron Spin Resonance Spectroscopy; D004926:Escherichia coli / Q000201:enzymology* / Q000378:metabolism; D006418:Heme / Q000737:chemistry; D006639:Histidine / Q000737:chemistry; D006912:Hydroxyquinolines / Q000737:chemistry; D007700:Kinetics; D008239:Lysine / Q000737:chemistry; D008956:Models, Chemical; D008958:Models, Molecular; D009154:Mutation; D009284:Naphthols / Q000737:chemistry; D050901:Nitrate Reductase; D009565:Nitrate Reductases / Q000737:chemistry*; D010088:Oxidoreductases / Q000737:chemistry; D010100:Oxygen / Q000737:chemistry; D010416:Pentachlorophenol / Q000737:chemistry; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D011522:Protons; D013729:Terpenes / Q000737:chemistry; D014451:Ubiquinone / Q000031:analogs & derivatives* / Q000737:chemistry
chemical_list: D006912:Hydroxyquinolines; D009284:Naphthols; D011522:Protons; D013729:Terpenes; D014451:Ubiquinone; C001333:2-(n-heptyl)-4-hydroxyquinoline N-oxide; C066500:menaquinol 6; D006418:Heme; D006639:Histidine; D010416:Pentachlorophenol; D010088:Oxidoreductases; D009565:Nitrate Reductases; D050901:Nitrate Reductase; D008239:Lysine; C003741:ubiquinol; D010100:Oxygen