Allosteric Cooperativity in Proton Energy Conversion in A1-Type Cytochrome c Oxidase

J Mol Biol. 2020 Jan 17;432(2):534-551. doi: 10.1016/j.jmb.2019.09.027. Epub 2019 Oct 15.

Abstract

Cytochrome c oxidase (CcO), the CuA, heme a, heme a3, CuB enzyme of respiratory chain, converts the free energy released by aerobic cytochrome c oxidation into a membrane electrochemical proton gradient (ΔμH+). ΔμH+ derives from the membrane anisotropic arrangement of dioxygen reduction to two water molecules and transmembrane proton pumping from a negative (N) space to a positive (P) space separated by the membrane. Spectroscopic, potentiometric, and X-ray crystallographic analyses characterize allosteric cooperativity of dioxygen binding and reduction with protonmotive conformational states of CcO. These studies show that allosteric cooperativity stabilizes the favorable conformational state for conversion of redox energy into a transmembrane ΔμH+.

Keywords: Allostery; Cytochromes; Proton pump; Redox enzymes; Respiratory chain.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Allosteric Regulation / genetics*
  • Binding Sites / genetics
  • Crystallography, X-Ray
  • Electron Transport / genetics
  • Electron Transport Complex IV / chemistry*
  • Electron Transport Complex IV / genetics
  • Electron Transport Complex IV / ultrastructure
  • Heme / analogs & derivatives*
  • Heme / chemistry
  • Heme / genetics
  • Oxygen / chemistry
  • Protein Binding / genetics
  • Proton Pumps / chemistry*
  • Proton Pumps / genetics
  • Proton Pumps / ultrastructure
  • Protons

Substances

  • Proton Pumps
  • Protons
  • heme a
  • Heme
  • Electron Transport Complex IV
  • Oxygen