Interaction of cytochrome c with cytochrome oxidase: two different docking scenarios.
Cytochrome c is the specific and efficient electron transfer mediator between the two last redox complexes of the mitochondrial respiratory chain. Its interaction with both partner proteins, namely cytochrome c(1) (of complex III) and the hydrophilic Cu(A) domain (of subunit II of oxidase), is transient, and known to be guided mainly by electrostatic interactions, with a set of acidic residues on the presumed docking site on the Cu(A) domain surface and a complementary region of opposite charges exposed on cytochrome c. Information from recent structure determinations of oxidases from both mitochondria and bacteria, site-directed mutagenesis approaches, kinetic data obtained from the analysis of isolated soluble modules of interacting redox partners, and computational approaches have yielded new insights into the docking and electron transfer mechanisms. Here, we summarize and discuss recent results obtained from bacterial cytochrome c oxidases from both Paracoccus denitrificans, in which the primary electrostatic encounter most closely matches the mitochondrial situation, and the Thermus thermophilus ba(3) oxidase in which docking and electron transfer is predominantly based on hydrophobic interactions.
Maneg
Oliver
O
Molecular Genetics, Institute of Biochemistry, Biozentrum N200, Goethe Universität, Marie-Curie-Str. 9, D-60439 Frankfurt, Germany. O.Maneg@em.uni-frankfurt.de
Malatesta
Francesco
F
Ludwig
Bernd
B
Drosou
Viktoria
V
D020134:Catalytic Domain / Q000235:genetics; D045304:Cytochromes c / Q000737:chemistry* / Q000378:metabolism*; D004579:Electron Transport; D003576:Electron Transport Complex IV / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D007700:Kinetics; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D019906:Nuclear Magnetic Resonance, Biomolecular; D010084:Oxidation-Reduction; D010231:Paracoccus denitrificans / Q000201:enzymology / Q000235:genetics; D055672:Static Electricity; D016963:Thermus thermophilus / Q000201:enzymology
D045304:Cytochromes c; D003576:Electron Transport Complex IV