PROSITE documentation PDOC00767
Succinate dehydrogenase cytochrome b subunit signatures


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-sulfur protein, and a hydrophobic component composed of a cytochrome B and a membrane anchor protein. The cytochrome b component is a mono heme transmembrane protein [1,2,3] belonging to a family that groups:

  • Cytochrome b-556 from bacterial SDH (gene sdhC).
  • Cytochrome b560 from the mammalian mitochondrial SDH complex.
  • Cytochrome b560 subunit 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.

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 heme group. We developed two signature patterns that include these histidine residues.


The di-heme cytochrome b-558 from Bacillus subtilis SDH complex is not a member of this family.

Last update:

May 2004 / Text revised.


Technical section

PROSITE methods (with tools and information) covered by this documentation:

SDH_CYT_1, PS01000; Succinate dehydrogenase cytochrome b subunit signature 1  (PATTERN)

SDH_CYT_2, PS01001; Succinate dehydrogenase cytochrome b subunit signature 2  (PATTERN)


1AuthorsYu L. Wei Y.-Y. Usui S. Yu C.-A.
TitleCytochrome b560 (QPs1) of mitochondrial succinate-ubiquinone reductase. Immunochemistry, cloning, and nucleotide sequencing.
SourceJ. Biol. Chem. 267:24508-24515(1992).
PubMed ID1447196

2AuthorsAbraham P.R. Mulder A. van 't Riet J. Raue H.A.
TitleCharacterization of the Saccharomyces cerevisiae nuclear gene CYB3 encoding a cytochrome b polypeptide of respiratory complex II.
SourceMol. Gen. Genet. 242:708-716(1994).
PubMed ID8152421

3AuthorsLeblanc C. Boyen C. Richard O. Bonnard G. Grienenberger J.M. Kloareg B.
TitleComplete sequence of the mitochondrial DNA of the rhodophyte Chondrus crispus (Gigartinales). Gene content and genome organization.
SourceJ. Mol. Biol. 250:484-495(1995).
PubMed ID7616569

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