InterPro domain: IPR021325

Cofactor maturation pathways such as the CCB system (system IV) for cytochrome c-heme attachment are conserved in all organisms performing oxygenic photosynthesis [ 1 ]. The CCB system consists of four proteins: CCB1-4. CCB2 and CCB4 are paralogues derived from a unique cyanobacterial ancestor [ 2 ]. Orthologues are conserved in higher plants [ 2 ].

1. A specific c-type cytochrome maturation system is required for oxygenic photosynthesis. Proc. Natl. Acad. Sci. U.S.A. 104, 9906-10
2. A novel pathway of cytochrome c biogenesis is involved in the assembly of the cytochrome b6f complex in arabidopsis chloroplasts. J. Biol. Chem. 283, 24608-16