Maturase Assemblies in Cytochrome c Biogenesis

Project Summary

C-type cytochromes contain one or multiple covalently linked heme cofactors and are among most widespread and versatile cofactor-containing proteins in all domains of life. Heme attachment is a posttranslational modification mediated by a dedicated maturation machinery that scans the nascent peptide upon membrane translocation and recognizes conserved binding motifs, CXnCH, to which the cofactors are then bound via thioether links. Known maturase machineries are able to recognize their target motifs in any sequence context and may have dozens of individual apoprotein targets in a single organism. In the present project we will characterize the components of the two most versatile maturases, the Ccm system (for cytochrome c maturation) and its close relative, the Ccs system (for cytochrome c synthase), in both the structural and the functional aspects.