Structure, topology and function of the translocase of the outer membrane of mitochondria

Plant Physiol Biochem. 2008 Mar;46(3):265-74. doi: 10.1016/j.plaphy.2007.12.012. Epub 2008 Jan 3.


Proteins destined for the mitochondria required the evolution of specific and efficient molecular machinery for protein import. The subunits of the import translocases of the inner membrane (TIM) appear homologous and conserved amongst species, however the components of the translocase of the outer membrane (TOM) show extensive differences between species. Recently, bioinformatic and structural analysis of Tom20, an important receptor subunit of the TOM complex, suggests that this protein complex arose from different ancestors for plants compared to animals and fungi, but has subsequently converged to provide similar functions and analogous structures. Here we review the current knowledge of the TOM complex, the function and structure of the various subunits that make up this molecular machine.

Publication types

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

MeSH terms

  • Membrane Transport Proteins / chemistry
  • Membrane Transport Proteins / metabolism*
  • Membrane Transport Proteins / physiology
  • Mitochondrial Membranes / metabolism*
  • Mitochondrial Proteins / chemistry
  • Mitochondrial Proteins / metabolism*
  • Mitochondrial Proteins / physiology
  • Models, Biological
  • Models, Molecular
  • Protein Structure, Tertiary


  • Membrane Transport Proteins
  • Mitochondrial Proteins