InterPro domain: IPR045062

This family represents proteins involved in cytochrome c assembly in mitochondria, chloroplast and bacteria; including CcmC from Escherichia coli [ 1 ] and CcsA from Chlamydomonas [ 2 ]. CcsA is called ResC in Bacillus (where there is additional N-terminal sequence) [ 3 ], while chloroplast proteins are consistently named CcsA.

CcmC interacts directly with heme, and it is the only protein of the ccm operon that is strictly required for heme transfer [ 4 ]. CcsA is required during biogenesis of c-type cytochromes at the step of heme attachment [ 5 ].

1. Escherichia coli genes required for cytochrome c maturation. J. Bacteriol. 177, 4321-6
2. The plastid-encoded ccsA gene is required for heme attachment to chloroplast c-type cytochromes. J. Biol. Chem. 271, 4632-9
3. Genes required for cytochrome c synthesis in Bacillus subtilis. Mol. Microbiol. 36, 638-50
4. Heme transfer to the heme chaperone CcmE during cytochrome c maturation requires the CcmC protein, which may function independently of the ABC-transporter CcmAB. Proc. Natl. Acad. Sci. U.S.A. 96, 6462-7