The three-dimensional structure of a proton-pumping pathway, the H-pathway, is evolutionarily conserved in all three families of cytochrome <i>c</i> oxidase.

ABSTRACT: The O₂ reduction site of bovine cytochrome c oxidase (CcO) comprises two redox-active metal centers: Fe _a3 and Cu_B. O₂ is reduced at Fe _a3 by four electrons transferred from cytochrome c in the P-side phase. Three proton-conducting pathways, D, K, and H, have been identified. Two distinct proton-pumping mechanisms, the D- and H-pathway mechanisms, proposed over 30 years ago, remain a subject of active debate. The former proposes that D-pathway transfers both pumping and water forming protons, whereas the latter proposes that the H-pathway transfers the pumping protons. CcOs are distributed across all aerobic organisms and are classified into evolutionarily related families: A, B, and C. In this study, we ana

SUBMITTER: Shimada A 

PROVIDER: S-EPMC12901375 | biostudies-literature | 2025

REPOSITORIES: biostudies-literature