Structure of a mitochondrial supercomplex formed by respiratory-chain complexes I and III

Proc Natl Acad Sci U S A. 2005 Mar 1;102(9):3225-9. doi: 10.1073/pnas.0408870102. Epub 2005 Feb 15.

Abstract

Mitochondria are central to the efficient provision of energy for eukaryotic cells. The oxidative-phosphorylation system of mitochondria consists of a series of five major membrane complexes: NADH-ubiquinone oxidoreductase (commonly known as complex I), succinate-ubiquinone oxidoreductase (complex II), ubiquinol-cytochrome c oxidoreductase (cytochrome bc1 complex or complex III), cytochrome c-O2 oxidoreductase (complex IV), and F1F0-ATP synthase (complex V). Several lines of evidence have recently suggested that complexes I and III-V might interact to form supercomplexes. However, because of their fragility, the structures of these supercomplexes are still unknown. A stable supercomplex consisting of complex I and dimeric complex III was purified from plant mitochondria. Structural characterization by single-particle EM indicates a specific type of interaction between monomeric complex I and dimeric complex III in a 1:1 ratio. We present a model for how complexes I and III are spatially organized within the I+III2 supercomplex.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis
  • Electron Transport
  • Electron Transport Complex I / chemistry
  • Electron Transport Complex I / isolation & purification
  • Electron Transport Complex I / metabolism*
  • Electron Transport Complex I / ultrastructure
  • Electron Transport Complex III / chemistry
  • Electron Transport Complex III / isolation & purification
  • Electron Transport Complex III / metabolism*
  • Electron Transport Complex III / ultrastructure
  • Electrophoresis, Polyacrylamide Gel
  • Microscopy, Electron
  • Models, Molecular
  • Protein Conformation

Substances

  • Electron Transport Complex I
  • Electron Transport Complex III