Functional roles of the heme architecture and its environment in tetraheme cytochrome c.
Cytochromes are involved in a wide variety of redox reactions in living systems. Some of them contain multiple hemes such as Desulfovibrio cytochrome c3 and Shewanella small tetraheme cytochrome c. The significance of c-type tetraheme architectures was discussed. A cyclic heme architecture and its environment regulate the extremely low redox potentials of cytochrome c3 in addition to bis-imidazole coordination and heme exposure. Each heme in cytochrome c3 plays a different role in the electron transport to/from [NiFe] hydrogenase and the specific CO-binding. In contrast, the chain-like heme architecture in Shewanella small tetraheme cytochrome c and soluble fumarate reductase provides a pathway for directional electron transfer. Thus, the tetraheme architectures do not comprise simple heme assemblies but sophisticated devices.
Akutsu
Hideo
H
Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita 565-0871, Japan. akutsu@protein.osaka-u.ac.jp
Takayama
Yuki
Y
D003574:Cytochrome c Group / Q000096:biosynthesis / Q000737:chemistry* / Q000235:genetics; D045304:Cytochromes c / Q000096:biosynthesis / Q000737:chemistry* / Q000235:genetics; D004579:Electron Transport; D004926:Escherichia coli / Q000235:genetics; D006418:Heme / Q000737:chemistry* / Q000502:physiology*; D008968:Molecular Conformation; D010084:Oxidation-Reduction; D010957:Plasmids / Q000235:genetics; D011487:Protein Conformation; D020592:Shewanella / Q000235:genetics
D003574:Cytochrome c Group; D006418:Heme; D045304:Cytochromes c; C017165:cytochrome c(3)