Members of this protein family are multiheme cytochrome c proteins of Methanosarcina acetivorans C2A and several other archaeal methanogens. All members have N-terminal signal peptides and are presumed to act in electron transfer reactions associated with methanogenesis. Putative heme-binding motifs include five (or six) CXXCH motifs, a CXXXCH motif, and a CXXXXCH motif. These proteins show multiple regions of local homology, in the same order, with multiheme cytochrome c proteins such as octaheme tetrathionate reductase from Shewanella.
Jiyao W et al.(2023). "The conserved domain database in 2023.",