A cytochrome c oxidase proton pumping mechanism that excludes the O2 reduction site

摘要

>A redox-coupled conformational change in Asp51 of subunit I and a hydrogen-bond network connecting Asp51 with the matrix surface have been deduced from X-ray structures of bovine heart cytochrome c oxidase. This has provided evidence that Asp51 may play a role in the proton pumping process. However, the lack of complete conservation of a residue analogous to Asp51, the inclusion of a peptide bond in the hydrogen-bonding network and the lack of apparent involvement of the O₂ reduction site have been used as arguments against the involvement of Asp51 in the mechanism of proton pumping. This minireview re-examines these arguments.