Substrate recognition of holocytochrome c synthase: N-terminal region and CXXCH motif of mitochondrial cytochrome c

Holocytochrome c synthase (HCCS) attaches heme covalently to mitochondrial respiratory cytochromes c. Little is known about the reaction of heme attachment to apocytochromes c by HCCS, although recently it has been established that the CXXCH motif and the N-terminus of the apocytochrome polypeptide are important protein-protein recognition motifs. Here, we explore further the important features of the N-terminal sequence and investigate what variations in the CXXCH residues are productively recognised by HCCS in its substrate. (C) 2014 The Authors. Published by Elsevier B.V. on behalf of the Federation of European Biochemical Societies.