title: The proton pump of the mitochondrial bc1 complex.
abstract: The molecular mechanism of the proton pump activity by the respiratory chain bc1 complex is still unknown. This group has proposed since long time that protonation/deprotonation events in the apoproteins of the complex are cooperatively linked to the oxido-reduction reactions at the quinone catalytic centre. Protolytic residues in the apoproteins can thus provide proton transfer pathways between the bulk aqueons phases and the redox centre. A series of experiments has been carried out aimed at demonstrating a role of particular complex subunits in the pump process. In this paper recent results are reviewed which have evidenced a definite role of polypeptide carboxyl residues in the proton pump mechanism. In particular, experiments carried out with both the bovine and P. denitrificans purified enzymes have indicated a specific involvement of aspartic residue(s) in the Rieske Fe/S protein in the proton pump function.
authors.affiliation: Department of Medical Biochemistry and Biology, University of Bari, Bari, Italy.
authors.forename: Tiziana
authors.initials: T
authors.lastname: Cocco
authors.forename: Marco
authors.initials: M
authors.lastname: Di Paola
authors.forename: Sergio
authors.initials: S
authors.lastname: Papa
authors.forename: Michele
authors.initials: M
authors.lastname: Lorusso
mesh_terms: D000818:Animals; D002417:Cattle; D014450:Electron Transport Complex III / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D004583:Electrons; D006863:Hydrogen-Ion Concentration; D008928:Mitochondria / Q000201:enzymology*; D009154:Mutation; D010084:Oxidation-Reduction; D010231:Paracoccus denitrificans / Q000201:enzymology; D011485:Protein Binding; D017494:Proton Pumps / Q000502:physiology*; D011522:Protons
chemical_list: D017494:Proton Pumps; D011522:Protons; D014450:Electron Transport Complex III