The terminal oxidases of Paracoccus denitrificans.
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.
de Gier
J W
JW
Department of Molecular and Cellular Biology, BioCentrum Amsterdam, Vrije Universiteit, The Netherlands.
Lübben
M
M
Reijnders
W N
WN
Tipker
C A
CA
Slotboom
D J
DJ
van Spanning
R J
RJ
Stouthamer
A H
AH
van der Oost
J
J
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
D001426:Bacterial Proteins; D011522:Protons; D006418:Heme; D010088:Oxidoreductases; C020094:duroquinol oxidase; D003576:Electron Transport Complex IV; D010100:Oxygen