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The structure of ubiquinol oxidase from Escherichia coli
Structural highlights
FunctionCYOB_ECOLI Cytochrome bo(3) ubiquinol terminal oxidase is the component of the aerobic respiratory chain of E.coli that predominates when cells are grown at high aeration. Has proton pump activity across the membrane in addition to electron transfer, pumping 2 protons/electron. Protons are probably pumped via D- and K- channels found in this subunit (PubMed:11017202).[1] [2] [3] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedCell respiration is catalyzed by the heme-copper oxidase superfamily of enzymes, which comprises cytochrome c and ubiquinol oxidases. These membrane proteins utilize different electron donors through dissimilar access mechanisms. We report here the first structure of a ubiquinol oxidase, cytochrome bo3, from Escherichia coli. The overall structure of the enzyme is similar to those of cytochrome c oxidases; however, the membrane-spanning region of subunit I contains a cluster of polar residues exposed to the interior of the lipid bilayer that is not present in the cytochrome c oxidase. Mutagenesis studies on these residues strongly suggest that this region forms a quinone binding site. A sequence comparison of this region with known quinone binding sites in other membrane proteins shows remarkable similarities. In light of these findings we suggest specific roles for these polar residues in electron and proton transfer in ubiquinol oxidase. The structure of the ubiquinol oxidase from Escherichia coli and its ubiquinone binding site.,Abramson J, Riistama S, Larsson G, Jasaitis A, Svensson-Ek M, Laakkonen L, Puustinen A, Iwata S, Wikstrom M Nat Struct Biol. 2000 Oct;7(10):910-7. PMID:11017202[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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