These
enzymes are
heterodimers of a
flavoprotein (fccBQ06530) and a diheme
cytochrome (fccA; Q06529) that carry out
hydrogen sulfide-dependent
cytochrome Creduction. The diheme cytochrome
folds into two domains, each of which resembles
mitochondrial cytochrome c, with the two
haem groups bound to the interior of the subunit. The flavoprotein subunit has a
glutathione reductase-like fold consisting of a beta(3,4)-alpha(3) core, and an alpha+beta sandwich. The
active site of the flavoprotein subunit contains a
catalytically important
disulfide bridge located above the
pyrimidine portion of the
flavin ring. The flavoprotein contains a
C-terminal domain required for binding to flavin, and subsequent electron transfer.[4]Electrons are transferred from the flavin to one of the haem groups in the cytochrome. Both
FAD and
heme C are covalently bound to the protein.
References
^Kusai K, Yamanaka T (November 1973). "The oxidation mechanisms of thiosulphate and sulphide in Chlorobium thiosulphatophilum: roles of cytochrome c-551 and cytochrome c-553". Biochimica et Biophysica Acta (BBA) - Bioenergetics. 325 (2): 304–14.
doi:
10.1016/0005-2728(73)90106-0.
PMID4357558.
^Fukumori Y, Yamanaka T (June 1979). "Flavocytochrome c of Chromatium vinosum. Some enzymatic properties and subunit structure". Journal of Biochemistry. 85 (6): 1405–14.
doi:
10.1093/oxfordjournals.jbchem.a132467.
PMID222744.
^Sorokin DY, Gray GO, Gaul DF, Knaff DB (April 1983). "Partial purification and characterization of two soluble c-type cytochromes from Chromatium vinosum". Archives of Biochemistry and Biophysics. 222 (1): 78–86.
doi:
10.1016/0003-9861(83)90504-0.
PMID6301383.
^
abcChen ZW, Koh M, Van Driessche G, Van Beeumen JJ, Bartsch RG, Meyer TE, Cusanovich MA, Mathews FS (October 1994). "The structure of flavocytochrome c sulfide dehydrogenase from a purple phototrophic bacterium". Science. 266 (5184): 430–2.
Bibcode:
1994Sci...266..430C.
doi:
10.1126/science.7939681.
PMID7939681.