title: The terminal oxidases of Paracoccus denitrificans.
abstract: Three distinct types of terminal oxidases participate in the aerobic respiratory pathways of Paracoccus denitrificans. Two alternative genes encoding subunit I of the aa3-type cytochrome c oxidase have been isolated before, namely ctaDI and ctaDII. Each of these genes can be expressed separately to complement a double mutant (delta ctaDI, delta ctaDII), indicating that they are isoforms of subunit I of the aa3-type oxidase. The genomic locus of a quinol oxidase has been isolated: cyoABC. This protohaem-containing oxidase, called cytochrome bb3, is the only quinol oxidase expressed under the conditions used. In a triple oxidase mutant (delta ctaDI, delta ctaDII, cyoB::KmR) an alternative cytochrome c oxidase has been characterized; this cbb3-type oxidase has been partially purified. Both cytochrome aa3 and cytochrome bb3 are redox-driven proton pumps. The proton-pumping capacity of cytochrome cbb3 has been analysed; arguments for and against the active transport of protons by this novel oxidase complex are discussed.
authors.affiliation: Department of Molecular and Cellular Biology, BioCentrum Amsterdam, Vrije Universiteit, The Netherlands.
authors.forename: J W
authors.initials: JW
authors.lastname: de Gier
authors.forename: M
authors.initials: M
authors.lastname: Lübben
authors.forename: W N
authors.initials: WN
authors.lastname: Reijnders
authors.forename: C A
authors.initials: CA
authors.lastname: Tipker
authors.forename: D J
authors.initials: DJ
authors.lastname: Slotboom
authors.forename: R J
authors.initials: RJ
authors.lastname: van Spanning
authors.forename: A H
authors.initials: AH
authors.lastname: Stouthamer
authors.forename: J
authors.initials: J
authors.lastname: van der Oost
mesh_terms: D000332:Aerobiosis; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000302:isolation & purification*; D001483:Base Sequence; D004579:Electron Transport; D003576:Electron Transport Complex IV / Q000235:genetics / Q000378:metabolism; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D006418:Heme / Q000032:analysis; D009876:Operon; D010088:Oxidoreductases / Q000235:genetics / Q000302:isolation & purification*; D010100:Oxygen / Q000378:metabolism; D010231:Paracoccus denitrificans / Q000201:enzymology* / Q000235:genetics; D011522:Protons; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity
chemical_list: D001426:Bacterial Proteins; D011522:Protons; D006418:Heme; D010088:Oxidoreductases; C020094:duroquinol oxidase; D003576:Electron Transport Complex IV; D010100:Oxygen