CYB_URSAR
ID CYB_URSAR Reviewed; 379 AA.
AC Q36192; Q36191; Q36193; Q36872; Q36938; Q36990; Q37052;
DT 01-NOV-1997, integrated into UniProtKB/Swiss-Prot.
DT 01-NOV-1997, sequence version 1.
DT 03-AUG-2022, entry version 99.
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 Ursus arctos (Brown bear) (Grizzly bear).
OG Mitochondrion.
OC Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia;
OC Eutheria; Laurasiatheria; Carnivora; Caniformia; Ursidae; Ursus.
OX NCBI_TaxID=9644;
RN [1]
RP NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC TISSUE=Skeletal muscle;
RX PubMed=8744769; DOI=10.1006/mpev.1996.0051;
RA Talbot S.L., Shields G.F.;
RT "A phylogeny of the bears (Ursidae) inferred from complete sequences of
RT three mitochondrial genes.";
RL Mol. Phylogenet. Evol. 5:567-575(1996).
RN [2]
RP NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX PubMed=7714914; DOI=10.1007/bf00166598;
RA Arnason U., Bodin K., Gullberg A., Ledje C., Mouchaty S.;
RT "A molecular view of pinniped relationships with particular emphasis on the
RT true seals.";
RL J. Mol. Evol. 40:78-85(1995).
RN [3]
RP NUCLEOTIDE SEQUENCE [GENOMIC DNA] OF 1-125.
RA Lento G.M., Hickson R.E., Chambers G.K., Penny D.;
RL Submitted (JAN-1995) 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 11 subunits: 3 respiratory
CC subunits (MT-CYB, CYC1 and UQCRFS1), 2 core proteins (UQCRC1 and
CC UQCRC2) and 6 low-molecular weight proteins (UQCRH/QCR6, UQCRB/QCR7,
CC UQCRQ/QCR8, UQCR10/QCR9, UQCR11/QCR10 and a cleavage product of
CC UQCRFS1). This cytochrome bc1 complex then forms a dimer.
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 -!- POLYMORPHISM: Sequenced in lineages GB01 to GB26.
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}.
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DR EMBL; U18870; AAB38167.1; -; Genomic_DNA.
DR EMBL; U18871; AAB38168.1; -; Genomic_DNA.
DR EMBL; U18872; AAB38169.1; -; Genomic_DNA.
DR EMBL; U18873; AAB38170.1; -; Genomic_DNA.
DR EMBL; U18874; AAB38171.1; -; Genomic_DNA.
DR EMBL; U18875; AAB38172.1; -; Genomic_DNA.
DR EMBL; U18876; AAB38173.1; -; Genomic_DNA.
DR EMBL; U18877; AAB38174.1; -; Genomic_DNA.
DR EMBL; U18878; AAB38175.1; -; Genomic_DNA.
DR EMBL; U18879; AAB38176.1; -; Genomic_DNA.
DR EMBL; U18880; AAB38177.1; -; Genomic_DNA.
DR EMBL; U18881; AAB38178.1; -; Genomic_DNA.
DR EMBL; U18882; AAB38179.1; -; Genomic_DNA.
DR EMBL; U18883; AAB38180.1; -; Genomic_DNA.
DR EMBL; U18884; AAB38181.1; -; Genomic_DNA.
DR EMBL; U18885; AAB38182.1; -; Genomic_DNA.
DR EMBL; U18886; AAB38183.1; -; Genomic_DNA.
DR EMBL; U18887; AAB38184.1; -; Genomic_DNA.
DR EMBL; U18888; AAB38185.1; -; Genomic_DNA.
DR EMBL; U18889; AAB38186.1; -; Genomic_DNA.
DR EMBL; U18890; AAB38187.1; -; Genomic_DNA.
DR EMBL; U18891; AAB38188.1; -; Genomic_DNA.
DR EMBL; U18892; AAB38189.1; -; Genomic_DNA.
DR EMBL; U18893; AAB38190.1; -; Genomic_DNA.
DR EMBL; U18894; AAB38191.1; -; Genomic_DNA.
DR EMBL; U18895; AAB38192.1; -; Genomic_DNA.
DR EMBL; U18896; AAB38193.1; -; Genomic_DNA.
DR EMBL; U18897; AAB38194.1; -; Genomic_DNA.
DR EMBL; X82308; CAA57751.1; -; Genomic_DNA.
DR EMBL; U12855; AAA67259.1; -; Genomic_DNA.
DR PIR; S58454; S58454.
DR AlphaFoldDB; Q36192; -.
DR SMR; Q36192; -.
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 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; Mitochondrion;
KW Mitochondrion inner membrane; Respiratory chain; Transmembrane;
KW Transmembrane helix; Transport; Ubiquinone.
FT CHAIN 1..379
FT /note="Cytochrome b"
FT /id="PRO_0000061703"
FT TRANSMEM 33..53
FT /note="Helical"
FT /evidence="ECO:0000250|UniProtKB:P00157"
FT TRANSMEM 77..98
FT /note="Helical"
FT /evidence="ECO:0000250|UniProtKB:P00157"
FT TRANSMEM 113..133
FT /note="Helical"
FT /evidence="ECO:0000250|UniProtKB:P00157"
FT TRANSMEM 178..198
FT /note="Helical"
FT /evidence="ECO:0000250|UniProtKB:P00157"
FT TRANSMEM 226..246
FT /note="Helical"
FT /evidence="ECO:0000250|UniProtKB:P00157"
FT TRANSMEM 288..308
FT /note="Helical"
FT /evidence="ECO:0000250|UniProtKB:P00157"
FT TRANSMEM 320..340
FT /note="Helical"
FT /evidence="ECO:0000250|UniProtKB:P00157"
FT TRANSMEM 347..367
FT /note="Helical"
FT /evidence="ECO:0000250|UniProtKB:P00157"
FT BINDING 83
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 97
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 182
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 196
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 201
FT /ligand="a ubiquinone"
FT /ligand_id="ChEBI:CHEBI:16389"
FT /evidence="ECO:0000250|UniProtKB:P00157"
FT VARIANT 57
FT /note="P -> S (in lineages GB01, GB02, GB03, GB04 and
FT GB05)"
FT VARIANT 89
FT /note="I -> M (in lineages GB01, GB02, GB03, GB04 and
FT GB05)"
FT VARIANT 110
FT /note="P -> S (in lineages GB01, GB02, GB03, GB04, GB05,
FT GB08, GB09, GB10, GB12, GB14 and GB17)"
FT VARIANT 123
FT /note="I -> V (in lineages GB01, GB02, GB03, GB04 and
FT GB05)"
FT VARIANT 153
FT /note="I -> V (in lineages GB01, GB02, GB03 and GB05)"
FT VARIANT 236
FT /note="A -> T (in lineages GB01, GB02, GB03, GB04 and
FT GB05)"
FT VARIANT 238
FT /note="T -> A (in lineages GB01, GB02, GB03, GB04 and
FT GB05)"
FT VARIANT 257
FT /note="T -> I (in lineages GB01, GB02, GB03, GB04 and
FT GB05)"
FT VARIANT 303
FT /note="I -> L (in lineages GB01, GB02, GB03, GB04 and
FT GB05)"
FT VARIANT 368
FT /note="I -> T (in lineage GB01)"
FT VARIANT 375
FT /note="N -> S (in lineages GB10 and GB12)"
SQ SEQUENCE 379 AA; 42459 MW; 0D82449AD05FF329 CRC64;
MTNIRKTHPL AKIINNSFID LPTPSNISAW WNFGSLLGVC LILQILTGLF LAMHYTPDTT
TAFSSVTHIC RDVHYGWVIR YVHANGASIF FICLFMHVGR GLYYGSYLFP ETWNIGIILL
FTIMATAFMG YVLPWGQMSF WGATVITNLL SAIPYIGTDL VEWIWGGFSV DKATLTRFFA
FHFILPFIIL ALAAVHLLFL HETGSNNPSG IPSDSDKIPF HPYYTIKDIL GALLLALTLA
TLVLFSPDLL GDPDNYTPAN PLSTPPHIKP EWYFLFAYAI LRSIPNKLGG VLALIFSILI
LAIIPLLHTS KQRGMMFRPL SQCLFWLLVA DLLTLTWIGG QPVEHPFIII GQLASILYFT
ILLVLMPIAG IIENNLLKW
