This family includes cytochromes c7 and c7-type. In cytochromes c7 all three haems are bis-His co-ordinated, while in c7-type the last haem is His-Met co-ordinated [1-4]. Desulfuromonas acetoxidans and Geobacter metallireducens cytochrome c7 participate in the anaerobic iron respiration, but Geobacter metallireducens cytochrome c7 hasn't a Fe(III) reductase activity [5]. This entry also includes cytochrome c nitrite reductase subunit NrfH from Desulfovibrio vulgaris which forms a complex with cytochrome c nitrite reductase NrfA [6].

1: Structure of a novel dodecaheme cytochrome c from Geobacter sulfurreducens reveals an extended 12 nm protein with interacting hemes. Pokkuluri PR, Londer YY, Duke NE, Pessanha M, Yang X, Orshonsky V, Orshonsky L, Erickson J, Zagyanskiy Y, Salgueiro CA, Schiffer M; J Struct Biol. 2011;174:223-233. PMID:21130881

2: Structural insights into the modulation of the redox properties of two Geobacter sulfurreducens homologous triheme cytochromes. Morgado L, Bruix M, Orshonsky V, Londer YY, Duke NE, Yang X, Pokkuluri PR, Schiffer M, Salgueiro CA; Biochim Biophys Acta. 2008;1777:1157-1165. PMID:18534185

3: Structure of a novel c7-type three-heme cytochrome domain from a multidomain cytochrome c polymer. Pokkuluri PR, Londer YY, Duke NE, Erickson J, Pessanha M, Salgueiro CA, Schiffer M; Protein Sci. 2004;13:1684-1692. PMID:15133162

4: Structural characterization of a family of cytochromes c(7) involved in Fe(III) respiration by Geobacter sulfurreducens. Pokkuluri PR, Londer YY, Yang X, Duke NE, Erickson J, Orshonsky V, Johnson G, Schiffer M; Biochim Biophys Acta. 2010;1797:222-232. PMID:19857457

5: Purification and characterization of triheme cytochrome c7 from the metal-reducing bacterium, Geobacter metallireducens. Afkar E, Fukumori Y; FEMS Microbiol Lett. 1999;175:205-210. PMID:10386369

6: X-ray structure of the membrane-bound cytochrome c quinol dehydrogenase NrfH reveals novel haem coordination. Rodrigues ML, Oliveira TF, Pereira IA, Archer M; EMBO J. 2006;25:5951-5960. PMID:17139260