ID CYB_CHEMY Reviewed; 381 AA. AC Q9TEC1; DT 04-JAN-2005, integrated into UniProtKB/Swiss-Prot. DT 01-MAY-2000, sequence version 1. DT 16-JAN-2019, 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 Chelonia mydas (Green sea-turtle) (Chelonia agassizi). OG Mitochondrion. OC Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; OC Archelosauria; Testudines; Cryptodira; Durocryptodira; Americhelydia; OC Chelonioidea; Cheloniidae; Chelonia. OX NCBI_TaxID=8469; RN [1] RP NUCLEOTIDE SEQUENCE [GENOMIC DNA]. RX PubMed=10368956; DOI=10.1093/oxfordjournals.molbev.a026163; RA Kumazawa Y., Nishida M.; RT "Complete mitochondrial DNA sequences of the green turtle and blue- RT tailed mole skink: statistical evidence for archosaurian affinity of RT turtles."; RL Mol. Biol. Evol. 16:784-792(1999). CC -!- FUNCTION: Component of the ubiquinol-cytochrome c reductase CC complex (complex III or cytochrome b-c1 complex) that is part of CC the mitochondrial respiratory chain. The b-c1 complex mediates CC electron transfer from ubiquinol to cytochrome c. Contributes to CC the generation of a proton gradient across the mitochondrial CC membrane that is then used for ATP synthesis. CC {ECO:0000250|UniProtKB:P00157}. CC -!- COFACTOR: CC Name=heme; Xref=ChEBI:CHEBI:30413; CC Evidence={ECO:0000250|UniProtKB:P00157}; CC Note=Binds 2 heme groups non-covalently. CC {ECO:0000250|UniProtKB:P00157}; CC -!- SUBUNIT: The cytochrome bc1 complex contains 3 respiratory CC subunits (MT-CYB, CYC1 and UQCRFS1), 2 core proteins (UQCRC1 and CC UQCRC2) and 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 CC at about 562 nm, and heme 2 (or BH or b566) is high-potential and CC absorbs at about 566 nm. {ECO:0000250}. CC -!- SIMILARITY: Belongs to the cytochrome b family. CC {ECO:0000255|PROSITE-ProRule:PRU00967, ECO:0000255|PROSITE- CC 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; AB012104; BAA79209.1; -; Genomic_DNA. DR RefSeq; NP_008776.1; NC_000886.1. DR ProteinModelPortal; Q9TEC1; -. DR SMR; Q9TEC1; -. DR GeneID; 808644; -. DR KEGG; cmy:808644; -. DR CTD; 4519; -. DR HOVERGEN; HBG017694; -. DR KO; K00412; -. DR OrthoDB; 1125966at2759; -. DR GO; GO:0016021; C:integral component of membrane; IEA:UniProtKB-KW. 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:0006122; P:mitochondrial electron transport, ubiquinol to cytochrome c; IEA:InterPro. DR CDD; cd00290; cytochrome_b_C; 1. DR CDD; cd00284; Cytochrome_b_N; 1. DR Gene3D; 1.20.810.10; -; 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; IPR016174; Di-haem_cyt_TM. DR Pfam; PF00032; Cytochrom_B_C; 1. DR Pfam; PF00033; Cytochrome_B; 1. DR PIRSF; PIRSF038885; COB; 1. DR SUPFAM; SSF81342; SSF81342; 1. DR SUPFAM; SSF81648; SSF81648; 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; KW Mitochondrion; Mitochondrion inner membrane; Respiratory chain; KW Transmembrane; Transmembrane helix; Transport; Ubiquinone. FT CHAIN 1 381 Cytochrome b. FT /FTId=PRO_0000060775. FT TRANSMEM 34 54 Helical. {ECO:0000250|UniProtKB:P00157}. FT TRANSMEM 78 99 Helical. {ECO:0000250|UniProtKB:P00157}. FT TRANSMEM 114 134 Helical. {ECO:0000250|UniProtKB:P00157}. FT TRANSMEM 179 199 Helical. {ECO:0000250|UniProtKB:P00157}. FT TRANSMEM 227 247 Helical. {ECO:0000250|UniProtKB:P00157}. FT TRANSMEM 289 309 Helical. {ECO:0000250|UniProtKB:P00157}. FT TRANSMEM 321 341 Helical. {ECO:0000250|UniProtKB:P00157}. FT TRANSMEM 348 368 Helical. {ECO:0000250|UniProtKB:P00157}. FT METAL 84 84 Iron 1 (heme b562 axial ligand). FT {ECO:0000250|UniProtKB:P00157}. FT METAL 98 98 Iron 2 (heme b566 axial ligand). FT {ECO:0000250|UniProtKB:P00157}. FT METAL 183 183 Iron 1 (heme b562 axial ligand). FT {ECO:0000250|UniProtKB:P00157}. FT METAL 197 197 Iron 2 (heme b566 axial ligand). FT {ECO:0000250|UniProtKB:P00157}. FT BINDING 202 202 Ubiquinone. FT {ECO:0000250|UniProtKB:P00157}. SQ SEQUENCE 381 AA; 42859 MW; DE980F3AFE9E17D7 CRC64; MATNLRKTHP MMKIINNLVI DLPSPSNISA WWNFGSLLAT CLALQIITGI FLAMHYSPDI SMAFSSIAHI TRDVQYGWLI RNMHANGASL FFMCIYLHIG RGIYYGSYLY KETWNTGIIL LLLVMATAFV GYVLPWGQMS FWGATVITNL LSAIPYIGNT LVQWIWGGFS VDNATLTRFF TFHFLLPFAI TGLTAVHLLF LHETGSNNPT GLNSNTDKIP FHPYFSYKDL LGLILMLTFL LTLTLFSPYL LGDPDNFTPA NPLSTPPHIK PEWYFLFAYA ILRSIPNKLG GVLALLFSIL ILFLMPTLHT SKQRTASFRP LTQILFWSLV ADLLVLTWIG GQPVEDPFII IGQVASTFYF LILLLLMPAA GMIENKMLNL K //