Influence of structure, pH and membrane potential on proton movement in cytochrome oxidase.
Cytochrome c oxidase (CcO) reconstituted into phospholipid vesicles and subject to a membrane potential, exhibits different characteristics than the free enzyme, with respect to effects of mutations, pH, inhibitors, and native structural differences between CcO from different species. The results indicate that the membrane potential influences the conformation of CcO and the direction of proton movement in the exit path. The importance of the protein structure above the hemes in proton exit, back leak and respiratory control is discussed.
Mills
Denise A
DA
Biochemistry and Molecular Biology Department, Michigan State University, East Lansing 48824, USA. millsden@msu.edu
Ferguson-Miller
Shelagh
S
D001693:Biological Transport, Active; D003576:Electron Transport Complex IV / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008564:Membrane Potentials; D008958:Models, Molecular; D010084:Oxidation-Reduction; D011487:Protein Conformation; D011522:Protons; D012242:Rhodobacter sphaeroides
D011522:Protons; D003576:Electron Transport Complex IV