Final Activity Report Summary - GIEGE-ERG (Cytochrome c biogenesis in higher plant mitochondria)
Mitochondria are considered to be power stations in the plant cell. In mitochondria, the respiratory chain uses cytochrome c as an electron transporter. These cytochromes distinguish themselves by the covalent attachment of the heme to the apoprotein. Altogether, the terms 'maturation' or 'biogenesis' of cytochrome c describe all the mechanisms comprising the binding of the heme to the apocytochrome, the transport of both components to their assembly site, the inter membrane space as well as protein and heme reduction mechanisms necessary for the covalent binding of the heme.
Surprisingly, in plant mitochondria, cytochrome c are assembled by a complex mechanism, similar to the one described in some bacteria. Several proteins involved in this pathway have already been identified by their sequence similarity with bacterial cytochrome c maturation proteins (CCM proteins). However, many proteins predicted by the bacterial model are yet to be characterised in plant mitochondria.
During this project the following results have been obtained:
The analysis of protein complexes containing CCM proteins by BN-PAGE has shown the existence of 480, 900, 500 and 500 kDa that can be in interaction with complexes of the respiratory chain Protein-protein interactions of CCM proteins have been studied. These experiments show that there are interactions of CCMH with apocytochrome c and also some interactions between CCMA and CcmB, the components of an ABC transporter. An appreciation of the expression of ccm genes has been done using a CATMA microarrays and is now analysed. Further analysis will now be done in the laboratory.
Surprisingly, in plant mitochondria, cytochrome c are assembled by a complex mechanism, similar to the one described in some bacteria. Several proteins involved in this pathway have already been identified by their sequence similarity with bacterial cytochrome c maturation proteins (CCM proteins). However, many proteins predicted by the bacterial model are yet to be characterised in plant mitochondria.
During this project the following results have been obtained:
The analysis of protein complexes containing CCM proteins by BN-PAGE has shown the existence of 480, 900, 500 and 500 kDa that can be in interaction with complexes of the respiratory chain Protein-protein interactions of CCM proteins have been studied. These experiments show that there are interactions of CCMH with apocytochrome c and also some interactions between CCMA and CcmB, the components of an ABC transporter. An appreciation of the expression of ccm genes has been done using a CATMA microarrays and is now analysed. Further analysis will now be done in the laboratory.