title: The three-subunit cytochrome bc1 complex of Paracoccus denitrificans. Its physiological function, structure, and mechanism of electron transfer and energy transduction.
abstract: The cytochrome bc1 complex purified from P. denitrificans has the same electron-transfer and energy-transducing activities, is sensitive to the same electron-transfer inhibitors, and contains cytochromes b, c1, iron-sulfur protein, and thermodynamically stable ubisemiquinone identical to the counterpart complexes from mitochondria. However, the bacterial bc1 complex consists of only three proteins, the obligate electron-transfer proteins, while the mitochondrial complexes contain six or more supernumerary polypeptides, which have no obvious electron-transfer function. The P. denitrificans complex is a paradigm for the bc1 complexes of all gram-negative bacteria. In addition, because of its simple polypeptide composition and apparently minimal damage during isolation, the P. denitrificans bc1 complex is an ideal system in which to study structure-function relationships requisite to energy transduction linked to electron transfer.
authors.affiliation: Department of Biochemistry, Dartmouth Medical School, Hanover, New Hampshire 03756.
authors.forename: B L
authors.initials: BL
authors.lastname: Trumpower
mesh_terms: D004579:Electron Transport; D014450:Electron Transport Complex III / Q000378:metabolism*; D010231:Paracoccus denitrificans / Q000201:enzymology*; D013329:Structure-Activity Relationship
chemical_list: D014450:Electron Transport Complex III