A chemically explicit model for the mechanism of proton pumping in heme-copper oxidases.
A mechanism for proton pumping is described that is based on chemiosmotic principles and the detailed molecular structures now available for cytochrome oxidases. The importance of conserved water positions and a step-wise gated process of proton translocation is emphasized, where discrete electron transfer events are coupled to proton uptake and expulsion. The trajectory of each pumped proton is the same for all four substrate electrons. An essential role for the His-Tyr cross-linked species is discussed, in gating of the D- and K-channels and as an acceptor/donor of electrons and protons at the binuclear center.
Sharpe
Martyn A
MA
Department of Neurosurgery, The Methodist Hospital, Houston, TX 77030, USA. MASharpe@tmhs.org
Ferguson-Miller
Shelagh
S
D003300:Copper / Q000737:chemistry; D003576:Electron Transport Complex IV / Q000737:chemistry / Q000378:metabolism; D006418:Heme / Q000737:chemistry; D015640:Ion Channel Gating; D008274:Magnesium / Q000737:chemistry; D008954:Models, Biological; D008958:Models, Molecular; D010084:Oxidation-Reduction; D015221:Potassium Channels / Q000737:chemistry / Q000378:metabolism; D017494:Proton Pumps / Q000737:chemistry / Q000378:metabolism*; D018892:Proton-Motive Force; D055672:Static Electricity; D014867:Water / Q000737:chemistry
D015221:Potassium Channels; D017494:Proton Pumps; D014867:Water; D006418:Heme; D003300:Copper; D003576:Electron Transport Complex IV; D008274:Magnesium