Structure of yeast cytochrome c oxidase in a supercomplex with cytochrome bc1

Nat Struct Mol Biol. 2019 Jan;26(1):78-83. doi: 10.1038/s41594-018-0172-z. Epub 2018 Dec 31.

Abstract

Cytochrome c oxidase (complex IV, CIV) is known in mammals to exist independently or in association with other respiratory proteins to form supercomplexes (SCs). In Saccharomyces cerevisiae, CIV is found solely in an SC with cytochrome bc1 (complex III, CIII). Here, we present the cryogenic electron microscopy (cryo-EM) structure of S. cerevisiae CIV in a III2IV2 SC at 3.3 Å resolution. While overall similarity to mammalian homologs is high, we found notable differences in the supernumerary subunits Cox26 and Cox13; the latter exhibits a unique arrangement that precludes CIV dimerization as seen in bovine. A conformational shift in the matrix domain of Cox5A-involved in allosteric inhibition by ATP-may arise from its association with CIII. The CIII-CIV arrangement highlights a conserved interaction interface of CIII, albeit one occupied by complex I in mammalian respirasomes. We discuss our findings in the context of the potential impact of SC formation on CIV regulation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Electron Transport Complex III / genetics
  • Electron Transport Complex III / metabolism*
  • Electron Transport Complex IV / genetics
  • Electron Transport Complex IV / metabolism
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism
  • Microscopy, Electron
  • Mitochondrial Membranes
  • Mitochondrial Proteins / genetics
  • Mitochondrial Proteins / metabolism
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism*
  • Saccharomyces cerevisiae / ultrastructure
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism*

Substances

  • COX14 protein, S cerevisiae
  • Cox26 protein, S cerevisiae
  • Membrane Proteins
  • Mitochondrial Proteins
  • Saccharomyces cerevisiae Proteins
  • Cox5a protein, S cerevisiae
  • Electron Transport Complex IV
  • Electron Transport Complex III