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.
Original language | English |
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Pages (from-to) | 183-96 |
Number of pages | 14 |
Journal | Molecular Microbiology |
Volume | 13 |
Issue number | 2 |
DOIs | |
Publication status | Published - Jul 1994 |
Keywords
- Aerobiosis
- Amino Acid Sequence
- Bacterial Proteins
- Base Sequence
- Electron Transport
- Electron Transport Complex IV
- Genes, Bacterial
- Genetic Complementation Test
- Heme
- Operon
- Oxidoreductases
- Oxygen
- Paracoccus denitrificans
- Protons
- Sequence Alignment
- Sequence Homology, Amino Acid
- Species Specificity
- Comparative Study
- Journal Article
- Research Support, Non-U.S. Gov't