ID CYB_SINKE Reviewed; 371 AA. AC Q9MLD7; DT 01-JUN-2001, integrated into UniProtKB/Swiss-Prot. DT 01-OCT-2000, sequence version 1. DT 02-OCT-2024, entry version 92. 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 Sinomicrurus kelloggi (Kellogg's coral snake) (Calliophis kelloggi). OG Mitochondrion. OC Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; OC Lepidosauria; Squamata; Bifurcata; Unidentata; Episquamata; Toxicofera; OC Serpentes; Colubroidea; Elapidae; Elapinae; Sinomicrurus. OX NCBI_TaxID=114670; RN [1] RP NUCLEOTIDE SEQUENCE [GENOMIC DNA]. RA Slowinski J.B., Boundy J., Lawson R.; RT "The phylogenetic relationships of Asian coral snakes (Elapidae: Calliophis RT and Maticora) based on morphological and molecular characters."; RL Submitted (DEC-1999) to the EMBL/GenBank/DDBJ databases. 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; AF220408; AAF35311.1; -; Genomic_DNA. DR AlphaFoldDB; Q9MLD7; -. DR SMR; Q9MLD7; -. DR GO; GO:0005743; C:mitochondrial inner membrane; IEA:UniProtKB-SubCell. DR GO; GO:0045275; C:respiratory chain complex III; IEA:InterPro. DR GO; GO:0046872; F:metal ion binding; IEA:UniProtKB-KW. DR GO; GO:0008121; F:ubiquinol-cytochrome-c reductase activity; IEA:InterPro. DR GO; GO:0022904; P:respiratory electron transport chain; IEA:InterPro. DR CDD; cd00290; cytochrome_b_C; 1. DR CDD; cd00284; Cytochrome_b_N; 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..371 FT /note="Cytochrome b" FT /id="PRO_0000060708" FT TRANSMEM 25..45 FT /note="Helical" FT /evidence="ECO:0000250|UniProtKB:P00157" FT TRANSMEM 69..90 FT /note="Helical" FT /evidence="ECO:0000250|UniProtKB:P00157" FT TRANSMEM 105..125 FT /note="Helical" FT /evidence="ECO:0000250|UniProtKB:P00157" FT TRANSMEM 170..190 FT /note="Helical" FT /evidence="ECO:0000250|UniProtKB:P00157" FT TRANSMEM 218..238 FT /note="Helical" FT /evidence="ECO:0000250|UniProtKB:P00157" FT TRANSMEM 280..300 FT /note="Helical" FT /evidence="ECO:0000250|UniProtKB:P00157" FT TRANSMEM 312..332 FT /note="Helical" FT /evidence="ECO:0000250|UniProtKB:P00157" FT TRANSMEM 339..358 FT /note="Helical" FT /evidence="ECO:0000250|UniProtKB:P00157" FT BINDING 75 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 89 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 174 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 188 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 193 FT /ligand="a ubiquinone" FT /ligand_id="ChEBI:CHEBI:16389" FT /evidence="ECO:0000250|UniProtKB:P00157" SQ SEQUENCE 371 AA; 42188 MW; B6723C71E03BD70F CRC64; MSNQHTLLIS NLLPVGSNIS TWWNFGSMLL TCLILQITTG FFLAIHYTAN INLAFSSVTH IMRDVPYGWI MQNLHAIGAS MFFICIYIHI ARGLYYGLYM NKNVWLSGTT LLITLMATAF FGYVLPWGQM SFWAATVITN LLTAIPYLGT TITTWLWGGF SINDPTLTRF FALHFILPFA IISLSSIHII LLHNKGSNNP LGTNSDIDKI PFHPYHSYKD TLMTISLFIL MFTILSFSPD LFNDPENFSK ANPLVTPQHI KPEWYFLFAY GILRSIPNKL GGTLALLMSV TILMTAPFTH TSHMRPMTFR PLAQMAFWTL IATFITITWT ASKPVEPPFI IISQMTSILY FLFFIMNPLL GWTENKIMMN N //