X-ray structural analyses of azide-bound cytochrome c oxidases reveal that the H-pathway is critically important for the proton-pumping activity.

ABSTRACT: Cytochrome c oxidase (CcO) is the terminal oxidase of cellular respiration, reducing O₂ to water and pumping protons. X-ray structural features have suggested that CcO pumps protons via a mechanism involving electrostatic repulsions between pumping protons in the hydrogen-bond network of a proton-conducting pathway (the H-pathway) and net positive charges created upon oxidation of an iron site, heme a (Fe _a²⁺), for reduction of O₂ at another iron site, heme a₃ (Fe _a3²⁺). The protons for pumping are transferred to the hydrogen-bond network from the N-side via the water channel of the H-pathway. Back-leakage of protons to the N-side is thought to be blocked by closure of

SUBMITTER: Shimada A 

PROVIDER: S-EPMC6153300 | biostudies-literature | 2018 Sep

REPOSITORIES: biostudies-literature