New Insights into the Co-evolution of Cytochrome cReductase and the Mitochondrial Processing Peptidase

• Published in: The Journal of biological chemistry Vol. 273; no. 21; pp. 13143 - 13149
• Main Authors: Brumme, Stefanie, Kruft, Volker, Schmitz, Udo K., Braun, Hans-Peter
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 22.05.1998; American Society for Biochemistry and Molecular Biology
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.273.21.13143

The mitochondrial processing peptidase (MPP) is a heterodimeric enzyme that forms part of the cytochrome creductase complex from higher plants. Mitochondria from mammals and yeast contain two homologous enzymes: (i) an active MPP within the mitochondrial matrix and (ii) an inactive MPP within the cytochromec reductase complex. To elucidate the evolution of MPP, the cytochrome c reductase complexes from lower plants were isolated and tested for processing activity. Mitochondria were prepared from the staghorn fern Platycerium bifurcatum, from the horsetail Equisetum arvense, and from the colorless algaePolytomella, and cytochrome c reductase complexes were purified by a micro-isolation procedure based on Blue-native polyacrylamide gel electrophoresis and electroelution. This is the first report on the subunit composition of a respiratory enzyme complex from a fern or a horsetail. The cytochrome creductase complexes from P. bifurcatum and E. arvense are shown to efficiently process mitochondrial precursor proteins, whereas the enzyme complex from Polytomella lacks proteolytic activity. An evolutionary model is suggested that assumes a correlation between the presence of an active MPP within the cytochromec reductase complex and the occurrence of chloroplasts.