Could CuB be the site of redox linkage in cytochrome c oxidase?
This paper explores the proton pumping function of cytochrome c oxidase [ferrocytochrome-c:oxygen oxidoreductase (EC 1.9.3.1)] based upon redox linkage at the "high-potential" CuB center. A model is proposed that is derived from a redox-linked ligand exchange mechanism previously described for the CuA site. Qualitative analysis of this mechanism indicates that such a mechanism is feasible. However, the relatively short distance between CuB and cytochrome a3 implies that the uncoupling electron transfers are quite facile. In addition, the position of the CuB center with respect to the inner mitochondrial membrane argues against redox linkage at the CuB site.
Larsen
R W
RW
Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena 91125.
Pan
L P
LP
Musser
S M
SM
Li
Z Y
ZY
Chan
S I
SI
D001693:Biological Transport, Active; D003300:Copper / Q000737:chemistry*; D004579:Electron Transport; D003576:Electron Transport Complex IV / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007425:Intracellular Membranes / Q000502:physiology; D008024:Ligands; D008564:Membrane Potentials; D008928:Mitochondria / Q000502:physiology*; D008954:Models, Biological; D010084:Oxidation-Reduction
D008024:Ligands; D003300:Copper; D003576:Electron Transport Complex IV