title: Quinone and non-quinone redox couples in Complex III.
abstract: The Q cycle mechanism proposed by Peter Mitchell in the 1970's explicitly considered the modification of ubiquinone two-electron redox properties upon binding to Complex III to match the thermodynamics of the other single-electron redox cofactors in the complex, and guide electron transfer to support the generation of a proton electro-chemical gradient across native membranes. A better understanding of the engineering of Complex III is coming from a now moderately well defined thermodynamic description of the redox components as a function of pH, including the Qi/heme b(H) cluster. The redox properties of the most obscure component, Qo, is finally beginning to be resolved.
authors.affiliation: Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA 19104, USA.
authors.forename: Haibo
authors.initials: H
authors.lastname: Zhang
authors.forename: Sarah E
authors.initials: SE
authors.lastname: Chobot
authors.forename: Artur
authors.initials: A
authors.lastname: Osyczka
authors.forename: Colin A
authors.initials: CA
authors.lastname: Wraight
authors.forename: P Leslie
authors.initials: PL
authors.lastname: Dutton
authors.forename: Christopher C
authors.initials: CC
authors.lastname: Moser
mesh_terms: D014450:Electron Transport Complex III / Q000737:chemistry / Q000266:history* / Q000378:metabolism; D049673:History, 20th Century; D008954:Models, Biological; D010084:Oxidation-Reduction; D018892:Proton-Motive Force; D011809:Quinones / Q000737:chemistry; D013816:Thermodynamics
chemical_list: D011809:Quinones; D014450:Electron Transport Complex III