{"metadata":{"accession":"IPR004224","entry_id":null,"type":"family","go_terms":[{"identifier":"GO:0006099","name":"tricarboxylic acid cycle","category":{"code":"P","name":"biological_process"}}],"source_database":"interpro","member_databases":{"ncbifam":{"NF010072":"fumarate reductase cytochrome b subunit"},"cdd":{"cd00581":"QFR_TypeB_TM"},"pirsf":{"PIRSF000177":"Fumarate reductase, cytochrome b subunit"}},"integrated":null,"hierarchy":{"accession":"IPR000701","name":"Succinate dehydrogenase/fumarate reductase type B, transmembrane subunit","type":"Family","children":[{"accession":"IPR004224","name":"Fumarate reductase type B, transmembrane subunit","type":"Family","children":[]},{"accession":"IPR011138","name":"Succinate dehydrogenase cytochrome b558 subunit","type":"Family","children":[{"accession":"IPR016002","name":"Succinate dehydrogenase cytochrome b558 subunit, Firmicute","type":"Family","children":[]}]},{"accession":"IPR014312","name":"Succinate dehydrogenase, hydrophobic membrane anchor","type":"Family","children":[]},{"accession":"IPR014314","name":"Succinate dehydrogenase, cytochrome b556 subunit","type":"Family","children":[{"accession":"IPR039023","name":"Succinate dehydrogenase membrane subunit SdhC, prokaryotes","type":"Family","children":[]}]}]},"name":{"name":"Fumarate reductase type B, transmembrane subunit","short":"Fum_red_B_TM"},"description":[{"text":"<p>Quinol:fumarate reductase (QFR) couples the reduction of fumarate to succinate to the oxidation of quinol to quinone, the opposite reaction to that catalyzed by the related protein, succinate:quinone oxidoreductase (SQR). QFR and SQR complexes are collectively referred to as succinate:quinone oxidoreductases and are predicted to share similar structures, containing either 3 or 4 subunits  [[cite:PUB00007431]].</p>\r\n\r\n<p>Subunit A (the flavoprotein subunit) contains the site of fumarate reduction and a covalently bound flavin adenine dinucleotide prosthetic group. Subunit B (the iron protein subunit) contains three iron-sulphur centres. Subunit(s) C (and D) (the membrane anchor subunits or cytochrome b subunits) include the membrane-spanning segments and binds haem b molecules [[cite:PUB00007431]]. The composition of these hydrophobic, cytochrome B subunits varies depending on the enzyme subtype.\r\n\r\nType A have two polypeptides, with three transmembrane helices each, and contain two protoheme IX molecules (denoted heme bH and heme bL). Type B have one polypeptide with five transmembrane helices and contain heme bH and heme bL. Type C have the same polypeptide arrangement as Type A, but contains only one protoheme IX molecule, corresponding to heme bH. Type D have two polypeptides, with three transmembrane helices each, and are without heme [[cite:PUB00015792]].</p>","llm":false,"checked":false,"updated":false}],"wikipedia":null,"literature":{"PUB00007431":{"PMID":10586875,"ISBN":null,"volume":"402","issue":"6760","year":1999,"title":"Structure of fumarate reductase from Wolinella succinogenes at 2.2 A resolution.","URL":null,"raw_pages":"377-85","medline_journal":"Nature","ISO_journal":"Nature","authors":["Lancaster CR","Kroger A","Auer M","Michel H."],"DOI_URL":"http://dx.doi.org/10.1038/46483"},"PUB00015792":{"PMID":9210286,"ISBN":null,"volume":"1320","issue":"2","year":1997,"title":"Succinate: quinone oxidoreductases. Variations on a conserved theme.","URL":null,"raw_pages":"107-41","medline_journal":"Biochim Biophys Acta","ISO_journal":"Biochim. Biophys. Acta","authors":["Hagerhall C."],"DOI_URL":"http://dx.doi.org/10.1016/S0005-2728(97)00019-4"}},"set_info":null,"overlaps_with":[{"accession":"IPR034804","name":"Fumarate reductase/succinate dehydrogenase, transmembrane subunit","type":"homologous_superfamily"}],"counters":{"subfamilies":0,"domain_architectures":0,"interactions":0,"matches":721,"pathways":0,"proteins":721,"proteomes":381,"sets":0,"structural_models":{"alphafold":592,"bfvd":0},"structures":6,"taxa":828},"entry_annotations":{},"cross_references":{},"is_llm":false,"is_reviewed_llm":false,"is_updated_llm":false,"representative_structure":{"accession":"2bs2","name":"QUINOL:FUMARATE REDUCTASE FROM WOLINELLA SUCCINOGENES"}}}