ISSN:
1365-2958
Quelle:
Blackwell Publishing Journal Backfiles 1879-2005
Thema:
Biologie
,
Medizin
Notizen:
Three distinct types of terminal oxidases participate in the aerobic respiratory pathways of Paracoccus denitrificans. Two alternative genes encoding sub unit 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 (ActaDI, ActaDII), indicating that they are isoforms of subunit I of the aa3-type oxidase. The genomic locus of a quinol oxidase has been isolated: cyoABC. Thisprotohaem-containing oxidase, called cytochrome bb3, is the oniy quinoi oxidase expressed under the conditions used, in a triple oxidase mutant (ActaDI, ActaDII, cyoB::KmR) an alternative cyto-chrome 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.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1111/j.1365-2958.1994.tb00414.x
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