Journal of Bioenergetics and Biomembranes

, Volume 31, Issue 3, pp 259–274

Integration of the Mitochondrial-Processing Peptidase into the Cytochrome bc1 Complex in Plants

  • Elzbieta Glaser
  • Patrick Dessi

DOI: 10.1023/A:1005475930477

Cite this article as:
Glaser, E. & Dessi, P. J Bioenerg Biomembr (1999) 31: 259. doi:10.1023/A:1005475930477


The plant mitochondrial cytochrome bc1 complex, like nonplant mitochondrial complexes,consists of cytochromes b and c1, the Rieske iron–sulfur protein, two Core proteins, and fivelow-molecular mass subunits. However, in contrast to nonplant sources, the two Core proteinsare identical to subunits of the general mitochondrial processing peptidase (MPP). The MPPis a fascinating enzyme that catalyzes the specific cleavage of the diverse presequence peptidesfrom hundreds of the nuclear-encoded mitochondrial precursor proteins that are synthesizedin the cytosol and imported into the mitochondrion. Integration of the MPP into the bc1complex renders the bc1 complex in plants bifunctional, being involved both in electrontransport and in protein processing. Despite the integration of MPP into the bc1 complex,electron transfer as well as translocation of the precursor through the import channel areindependent of the protein-processing activity. Recognition of the processing site by MPPoccurs via the recognition of higher-order structural elements in combination with charge andcleavage-site properties. Elucidation of the three-dimensional (3-D) structure of the mammaliancytochrome bc1 complex is highly useful for understanding of the mechanism of action of MPP.

bc1 complexubiquinol:cytochrome c oxidoreductasecore proteinsmitochondrial-processing peptidaseplant mitochondriaprotein importpresequencemitochondrial biogenesis

Copyright information

© Plenum Publishing Corporation 1999

Authors and Affiliations

  • Elzbieta Glaser
  • Patrick Dessi

There are no affiliations available