title: Proton pumping by NADH:ubiquinone oxidoreductase. A redox driven conformational change mechanism?
abstract: The modular evolutionary origin of NADH:ubiquinone oxidoreductase (complex I) provides useful insights into its functional organization. Iron-sulfur cluster N2 and the PSST and 49 kDa subunits were identified as key players in ubiquinone reduction and proton pumping. Structural studies indicate that this 'catalytic core' region of complex I is clearly separated from the membrane. Complex I from Escherichia coli and Klebsiella pneumoniae was shown to pump sodium ions rather than protons. These new insights into structure and function of complex I strongly suggest that proton or sodium pumping in complex I is achieved by conformational energy transfer rather than by a directly linked redox pump.
authors.affiliation: Universität Frankfurt, Fachbereich Medizin, Institut für Biochemie I, Theodor-Stern-Kai 7, Haus 25B, D-60590 Frankfurt am Main, Germany. brandt@zbc.kgu.de
authors.forename: Ulrich
authors.initials: U
authors.lastname: Brandt
authors.forename: Stefan
authors.initials: S
authors.lastname: Kerscher
authors.forename: Stefan
authors.initials: S
authors.lastname: Dröse
authors.forename: Klaus
authors.initials: K
authors.lastname: Zwicker
authors.forename: Volker
authors.initials: V
authors.lastname: Zickermann
mesh_terms: D000595:Amino Acid Sequence; D016227:Benzoquinones / Q000032:analysis; D005075:Biological Evolution; D020134:Catalytic Domain; D042967:Electron Transport Complex I; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology; D017136:Ion Transport; D008969:Molecular Sequence Data; D009247:NADH, NADPH Oxidoreductases / Q000737:chemistry* / Q000378:metabolism; D010084:Oxidation-Reduction; D011487:Protein Conformation; D021122:Protein Subunits; D017494:Proton Pumps / Q000737:chemistry* / Q000378:metabolism; D011522:Protons; D012964:Sodium / Q000378:metabolism
chemical_list: D016227:Benzoquinones; D004791:Enzyme Inhibitors; D021122:Protein Subunits; D017494:Proton Pumps; D011522:Protons; C025232:semiquinone radicals; D012964:Sodium; D009247:NADH, NADPH Oxidoreductases; D042967:Electron Transport Complex I