title: Thermodynamics of electron transfer in Escherichia coli cytochrome bo3.
abstract: The proton translocation mechanism of the Escherichia coli cytochrome bo3 complex is intimately tied to the electron transfers within the enzyme. Herein we evaluate two models of proton translocation in this enzyme, a cytochrome c oxidase-type ion-pump and a Q-cycle mechanism, on the basis of the thermodynamics of electron transfer. We conclude that from a thermodynamic standpoint, a Q-cycle is the more favorable mechanism for proton translocation and is likely occurring in the enzyme.
authors.affiliation: Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, CA 91125, USA.
authors.forename: B E
authors.initials: BE
authors.lastname: Schultz
authors.forename: S I
authors.initials: SI
authors.lastname: Chan
mesh_terms: D000494:Allosteric Regulation; D003573:Cytochrome b Group; D003580:Cytochromes / Q000737:chemistry / Q000378:metabolism*; D004579:Electron Transport; D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins; D006873:Hydroquinones / Q000378:metabolism; D016623:Ion Pumps / Q000378:metabolism; D007700:Kinetics; D008564:Membrane Potentials; D008954:Models, Biological; D010084:Oxidation-Reduction; D011312:Pressure; D011522:Protons; D013816:Thermodynamics
chemical_list: D003573:Cytochrome b Group; D003580:Cytochromes; D029968:Escherichia coli Proteins; D006873:Hydroquinones; D016623:Ion Pumps; D011522:Protons; C083850:cytochrome bo3, E coli