Cytochrome o (bo) is a proton pump in Paracoccus denitrificans and Escherichia coli.
Spheroplasts from aerobically grown wild-type Paracoccus denitrificans cells respire with succinate despite specific inhibition of the cytochrome bc1 complex by myxothiazol. Coupled to this activity, which involves only b-type cytochromes, there is translocation of 1.5-1.9 h+/e- across the cytoplasmic membrane. Similar H+ translocation ratios are observed during oxidation of ubiquinol in spheroplasts from aerobically grown mutants of Paracoccus lacking cytochrome c oxidase, or deficient in cytochrome c, as well as in a strain of E. coli from which cytochrome d was deleted. These observations show that the cytochrome o complex is a proton pump much like cytochrome aa3 to which it is structurally related.
Puustinen
A
A
Department of Medical Chemistry, University of Helsinki, Finland.
Finel
M
M
Virkki
M
M
Wikström
M
M
D003573:Cytochrome b Group; D003580:Cytochromes / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology*; D029968:Escherichia coli Proteins; D010084:Oxidation-Reduction; D010101:Oxygen Consumption; D010231:Paracoccus denitrificans / Q000201:enzymology*; D011522:Protons; D013104:Spheroplasts / Q000201:enzymology; D014451:Ubiquinone / Q000031:analogs & derivatives / Q000378:metabolism
D003573:Cytochrome b Group; D003580:Cytochromes; D029968:Escherichia coli Proteins; D011522:Protons; D014451:Ubiquinone; C017168:cytochrome bo, E coli; C003741:ubiquinol