Structural and biochemical characterization of a quinol binding site of Escherichia coli nitrate reductase A.
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.
Bertero
Michela G
MG
Department of Biochemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada.
Rothery
Richard A
RA
Boroumand
Nasim
N
Palak
Monica
M
Blasco
Francis
F
Ginet
Nicolas
N
Weiner
Joel H
JH
Strynadka
Natalie C J
NC
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
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