Redox-Controlled Proton Gating in Bovine Cytochrome c Oxidase

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

Cytochrome c oxidase is the terminal enzyme in the electron transfer chain of essentially all organisms that utilize oxygen to generate energy. It reduces oxygen to water and harnesses the energy to pump protons across the mitochondrial membrane in eukaryotes and the plasma membrane in prokaryotes. The mechanism by which proton pumping is coupled to the oxygen reduction reaction remains unresolved, owing to the difficulty of visualizing proton movement within the massive membrane-associated protein matrix. Here, with a novel hydrogen/deuterium exchange resonance Raman spectroscopy method, we have identified two critical elements of the proton pump: a proton loading site near the propionate groups of heme a, which is capable of transiently storing protons uploaded from the negative-side of the membrane prior to their release into the positive side of the membrane and a conformational gate that controls proton translocation in response to the change in the redox state of heme a. These findings form the basis for a postulated molecular model describing a detailed mechanism by which unidirectional proton translocation is coupled to electron transfer from heme a to heme a3, associated with the oxygen chemistry occurring in the heme a3 site, during enzymatic turnover.

Original languageEnglish (US)
Article numbere63669
JournalPLoS One
Volume8
Issue number5
DOIs
StatePublished - May 16 2013

Fingerprint

Electron Transport Complex IV
cytochrome-c oxidase
protons
Oxidation-Reduction
heme
Protons
cattle
Oxygen
oxygen
Proton Pumps
proton pump
Membranes
Electrons
Raman spectroscopy
harness
molecular models
Molecular Models
Raman Spectrum Analysis
deuterium
Deuterium

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Medicine(all)

Cite this

Redox-Controlled Proton Gating in Bovine Cytochrome c Oxidase. / Egawa, Tsuyoshi; Yeh, Syun-Ru; Rousseau, Denis L.

In: PLoS One, Vol. 8, No. 5, e63669, 16.05.2013.

Research output: Contribution to journalArticle

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