National Center for
1Y4Z: The Crystal Structure Of Nitrate Reductase A, Narghi, In Complex With The Q-Site Inhibitor Pentachlorophenol
Structural and biochemical characterization of a quinol binding site of Escherichia coli nitrate reductase A
J. Biol. Chem. (2005) 280 p.14836-14843
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.