ID CYB_SCYCA Reviewed; 381 AA. AC O79413; DT 15-DEC-1998, integrated into UniProtKB/Swiss-Prot. DT 01-NOV-1998, sequence version 1. DT 02-SEP-2026, entry version 109. DE RecName: Full=Cytochrome b; DE AltName: Full=Complex III subunit 3; DE AltName: Full=Complex III subunit III; DE AltName: Full=Cytochrome b-c1 complex subunit 3; DE AltName: Full=Ubiquinol-cytochrome-c reductase complex cytochrome b subunit; GN Name=mt-cyb; Synonyms=cob, cytb, mtcyb; OS Scyliorhinus canicula (Small-spotted catshark) (Squalus canicula). OG Mitochondrion. OC Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Chondrichthyes; OC Elasmobranchii; Galeomorphii; Galeoidea; Carcharhiniformes; Scyliorhinidae; OC Scyliorhinus. OX NCBI_TaxID=7830; RN [1] RP NUCLEOTIDE SEQUENCE [GENOMIC DNA]. RC TISSUE=Muscle; RX PubMed=9725850; DOI=10.1093/genetics/150.1.331; RA Delarbre C., Spruyt N., Delmarre C., Gallut C., Barriel V., Janvier P., RA Laudet V., Gachelin G.; RT "The complete nucleotide sequence of the mitochondrial DNA of the dogfish, RT Scyliorhinus canicula."; RL Genetics 150:331-344(1998). CC -!- FUNCTION: Component of the ubiquinol-cytochrome c reductase complex CC (complex III or cytochrome b-c1 complex) that is part of the CC mitochondrial respiratory chain. The b-c1 complex mediates electron CC transfer from ubiquinol to cytochrome c. Contributes to the generation CC of a proton gradient across the mitochondrial membrane that is then CC used for ATP synthesis. {ECO:0000250|UniProtKB:P00157}. CC -!- COFACTOR: CC Name=heme b; Xref=ChEBI:CHEBI:60344; CC Evidence={ECO:0000250|UniProtKB:P00157}; CC Note=Binds 2 heme b groups non-covalently. CC {ECO:0000250|UniProtKB:P00157}; CC -!- SUBUNIT: The cytochrome bc1 complex contains 3 respiratory subunits CC (MT-CYB, CYC1 and UQCRFS1), 2 core proteins (UQCRC1 and UQCRC2) and CC probably 6 low-molecular weight proteins. CC {ECO:0000250|UniProtKB:P00157}. CC -!- SUBCELLULAR LOCATION: Mitochondrion inner membrane CC {ECO:0000250|UniProtKB:P00157}; Multi-pass membrane protein CC {ECO:0000250|UniProtKB:P00157}. CC -!- MISCELLANEOUS: Heme 1 (or BL or b562) is low-potential and absorbs at CC about 562 nm, and heme 2 (or BH or b566) is high-potential and absorbs CC at about 566 nm. {ECO:0000250}. CC -!- SIMILARITY: Belongs to the cytochrome b family. {ECO:0000255|PROSITE- CC ProRule:PRU00967, ECO:0000255|PROSITE-ProRule:PRU00968}. CC -!- CAUTION: The full-length protein contains only eight transmembrane CC helices, not nine as predicted by bioinformatics tools. CC {ECO:0000250|UniProtKB:P00157}. CC --------------------------------------------------------------------------- CC Copyrighted by the UniProt Consortium, see https://www.uniprot.org/terms CC Distributed under the Creative Commons Attribution (CC BY 4.0) License CC --------------------------------------------------------------------------- DR EMBL; Y16067; CAA76031.1; -; Genomic_DNA. DR PIR; T11312; T11312. DR RefSeq; NP_007626.1; NC_001950.1. DR AlphaFoldDB; O79413; -. DR SMR; O79413; -. DR GeneID; 808292; -. DR KEGG; scau:808292; -. DR CTD; 4519; -. DR OrthoDB; 244at2759; -. DR GO; GO:0005743; C:mitochondrial inner membrane; ISS:UniProtKB. DR GO; GO:0045275; C:respiratory chain complex III; IEA:InterPro. DR GO; GO:0008121; F:quinol-cytochrome-c reductase activity; IEA:InterPro. DR GO; GO:0006122; P:mitochondrial electron transport, ubiquinol to cytochrome c; IEA:TreeGrafter. DR CDD; cd00290; cytochrome_b_C; 1. DR CDD; cd00284; Cytochrome_b_N; 1. DR FunFam; 1.20.810.10:FF:000002; Cytochrome b; 1. DR Gene3D; 1.20.810.10; Cytochrome Bc1 Complex, Chain C; 1. DR InterPro; IPR005798; Cyt_b/b6_C. DR InterPro; IPR036150; Cyt_b/b6_C_sf. DR InterPro; IPR005797; Cyt_b/b6_N. DR InterPro; IPR027387; Cytb/b6-like_sf. DR InterPro; IPR030689; Cytochrome_b. DR InterPro; IPR048260; Cytochrome_b_C_euk/bac. DR InterPro; IPR048259; Cytochrome_b_N_euk/bac. DR InterPro; IPR016174; Di-haem_cyt_TM. DR PANTHER; PTHR19271; CYTOCHROME B; 1. DR PANTHER; PTHR19271:SF16; CYTOCHROME B; 1. DR Pfam; PF00032; Cytochrom_B_C; 1. DR Pfam; PF00033; Cytochrome_B; 1. DR PIRSF; PIRSF038885; COB; 1. DR SUPFAM; SSF81648; a domain/subunit of cytochrome bc1 complex (Ubiquinol-cytochrome c reductase); 1. DR SUPFAM; SSF81342; Transmembrane di-heme cytochromes; 1. DR PROSITE; PS51003; CYTB_CTER; 1. DR PROSITE; PS51002; CYTB_NTER; 1. PE 3: Inferred from homology; KW Electron transport; Heme; Iron; Membrane; Metal-binding; Mitochondrion; KW Mitochondrion inner membrane; Respiratory chain; Transmembrane; KW Transmembrane helix; Transport; Ubiquinone. FT CHAIN 1..381 FT /note="Cytochrome b" FT /id="PRO_0000061532" FT TRANSMEM 34..54 FT /note="Helical" FT /evidence="ECO:0000250|UniProtKB:P00157" FT TRANSMEM 78..99 FT /note="Helical" FT /evidence="ECO:0000250|UniProtKB:P00157" FT TRANSMEM 114..134 FT /note="Helical" FT /evidence="ECO:0000250|UniProtKB:P00157" FT TRANSMEM 179..199 FT /note="Helical" FT /evidence="ECO:0000250|UniProtKB:P00157" FT TRANSMEM 227..247 FT /note="Helical" FT /evidence="ECO:0000250|UniProtKB:P00157" FT TRANSMEM 289..309 FT /note="Helical" FT /evidence="ECO:0000250|UniProtKB:P00157" FT TRANSMEM 321..341 FT /note="Helical" FT /evidence="ECO:0000250|UniProtKB:P00157" FT TRANSMEM 348..368 FT /note="Helical" FT /evidence="ECO:0000250|UniProtKB:P00157" FT BINDING 84 FT /ligand="heme b" FT /ligand_id="ChEBI:CHEBI:60344" FT /ligand_label="b562" FT /ligand_part="Fe" FT /ligand_part_id="ChEBI:CHEBI:18248" FT /note="axial binding residue" FT /evidence="ECO:0000250|UniProtKB:P00157" FT BINDING 98 FT /ligand="heme b" FT /ligand_id="ChEBI:CHEBI:60344" FT /ligand_label="b566" FT /ligand_part="Fe" FT /ligand_part_id="ChEBI:CHEBI:18248" FT /note="axial binding residue" FT /evidence="ECO:0000250|UniProtKB:P00157" FT BINDING 183 FT /ligand="heme b" FT /ligand_id="ChEBI:CHEBI:60344" FT /ligand_label="b562" FT /ligand_part="Fe" FT /ligand_part_id="ChEBI:CHEBI:18248" FT /note="axial binding residue" FT /evidence="ECO:0000250|UniProtKB:P00157" FT BINDING 197 FT /ligand="heme b" FT /ligand_id="ChEBI:CHEBI:60344" FT /ligand_label="b566" FT /ligand_part="Fe" FT /ligand_part_id="ChEBI:CHEBI:18248" FT /note="axial binding residue" FT /evidence="ECO:0000250|UniProtKB:P00157" FT BINDING 202 FT /ligand="a ubiquinone" FT /ligand_id="ChEBI:CHEBI:16389" FT /evidence="ECO:0000250|UniProtKB:P00157" SQ SEQUENCE 381 AA; 43103 MW; C4B457072A56D0C5 CRC64; MATNIRKTHP LLKIVNHALI DLPAPSNISV WWNFGSLLGL CLIMQIITGL FLAMHYTADI SMAFSSVIHI SRDVNYGWLM RNIHAYGASF FFICIYLHIA RGLYYGSYLN KEAWNIGVVL LFLLMATAFV GYVLPWGQMS FWGATVITNL LSAFPYIGNL LVQWIWGGFS VDNATLTRFF AFHFLLPFLI LALSVIHILF LHETGANNPM GINSNTDKIS FHPYFSYKDL FGFLIVITLL ATLALFMPNL LGDAENFIPA NPLVTPLHIQ PEWYFLFAYA ILRSIPNKLG GVLALLFSIF ILLLVPLLHT SKLRSNIFRP LTQIFFWSLV TNAIILTWIG GQPVEQPFIM VGQIASVAYF SLFLFVIPIT SWCENKFLSL N //