Succinate dehydrogenase/Fumarate reductase, transmembrane subunit (IPR000701)

Short name: Succ_DH_Fumarate_Rdtase_TM-su

Family relationships


This entry includes the transmembrane subunit from both succinate dehydrogenase and fumarate reductase complexes.

Fumarate reductase couples the reduction of fumarate to succinate to the oxidation of quinol to quinone, in a reaction opposite to that catalysed by the related complex II of the respiratory chain (succinate dehydrogenase) [PMID: 10586875]. Three protein subunits contain the fumarate reductase complex. Subunit A contains the site of fumarate reduction and a covalently bound flavin adenine dinucleotide prosthetic group. Subunit B contains three iron-sulphur centres. The menaquinol-oxidizing subunit C consists of five membrane-spanning, primarily helical segments and binds two haem b molecules [PMID: 10586875].

Succinate dehydrogenase (SDH) is a membrane-bound complex of two main components: a membrane-extrinsic component composed of an FAD-binding flavoprotein and an iron-sulphur protein, and a hydrophobic component composed of a cytochrome b and a membrane anchor protein. The cytochrome b component is a mono-haem transmembrane protein [PMID: 1447196, PMID: 8152421, PMID: 7616569] belonging to a family that includes:

  • Cytochrome b-556 from bacterial SDH (gene sdhC).
  • Cytochrome b560 from the mammalian mitochondrial SDH complex, which is encoded in the mitochondrial genome of some algae and in the plant Marchantia polymorpha.
  • Cytochrome b from yeast mitochondrial SDH complex (gene SDH3 or CYB3).
  • Protein cyt-1 from Caenorhabditis elegans.

These cytochromes are proteins of about 130 residues that comprise three transmembrane regions. There are two conserved histidines which may be involved in binding the haem group.

GO terms

Biological Process

No terms assigned in this category.

Molecular Function

GO:0016627 oxidoreductase activity, acting on the CH-CH group of donors

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.