Flavocytochrome c sulfide dehydrogenase

Flavocytochrome c sulfide dehydrogenase, also known as Sulfide-cytochrome-c reductase (flavocytochrome c) (EC 1.8.2.3), is an enzyme with systematic name hydrogen-sulfide:flavocytochrome c oxidoreductase.^{[1][2][3][4][5][6]} It is found in sulfur-oxidising bacteria such as the purple phototrophic bacteria Allochromatium vinosum.^[4][7] This enzyme catalyses the following chemical reaction:

hydrogen sulfide + 2 ferricytochrome c ${\displaystyle \rightleftharpoons }$ sulfur + 2 ferrocytochrome c + 2 H⁺

Sulfide-cytochrome-c reductase (flavocytochrome c)
Structure of the flavocytochrome c sulfide dehydrogenase from the purple phototrophic bacterium Allochromatium vinosum (PDB: 1FCD​).
Identifiers
EC no.	1.8.2.3
Databases
IntEnz	IntEnz view
BRENDA	BRENDA entry
ExPASy	NiceZyme view
KEGG	KEGG entry
MetaCyc	metabolic pathway
PRIAM	profile
PDB structures	RCSB PDB PDBe PDBsum
Search PMC articles PubMed articles NCBI proteins

Flavocytochrome c sulfide dehydrogenase, flavin-binding
Identifiers
Symbol	FCSD-flav_bind
Pfam	PF09242
InterPro	IPR015323
SCOP2	1fcd / SCOPe / SUPFAM
Available protein structures: Pfam   structures / ECOD   PDB RCSB PDB; PDBe; PDBj PDBsum structure summary

These enzymes are heterodimers of a flavoprotein (fccB Q06530) and a diheme cytochrome (fccA; Q06529) that carry out hydrogen sulfide-dependent cytochrome C reduction. 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.