CYB_CHLRE
ID CYB_CHLRE Reviewed; 381 AA.
AC P23662; P23663;
DT 01-NOV-1991, integrated into UniProtKB/Swiss-Prot.
DT 01-NOV-1991, sequence version 1.
DT 03-AUG-2022, entry version 108.
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 Chlamydomonas reinhardtii (Chlamydomonas smithii).
OG Mitochondrion.
OC Eukaryota; Viridiplantae; Chlorophyta; core chlorophytes; Chlorophyceae;
OC CS clade; Chlamydomonadales; Chlamydomonadaceae; Chlamydomonas.
OX NCBI_TaxID=3055;
RN [1]
RP NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX PubMed=2250648; DOI=10.1007/bf00265056;
RA Michaelis G., Vahrenholz C., Pratje E.;
RT "Mitochondrial DNA of Chlamydomonas reinhardtii: the gene for apocytochrome
RT b and the complete functional map of the 15.8 kb DNA.";
RL Mol. Gen. Genet. 223:211-216(1990).
RN [2]
RP NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC STRAIN=CC-1373;
RX PubMed=1701210; DOI=10.1007/bf00265065;
RA Colleaux L., Michel-Wolwertz M.R., Matagne R.F., Dujon B.;
RT "The apocytochrome b gene of Chlamydomonas smithii contains a mobile intron
RT related to both Saccharomyces and Neurospora introns.";
RL Mol. Gen. Genet. 223:288-296(1990).
RN [3]
RP NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX PubMed=2103454; DOI=10.1007/bf00036921;
RA Ma D.-P., Yang Y.-W., King T.Y., Hasnain S.E.;
RT "The mitochondrial apocytochrome b gene from Chlamydomonas reinhardtii.";
RL Plant Mol. Biol. 15:357-359(1990).
RN [4]
RP NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC STRAIN=cw15;
RX PubMed=1831072; DOI=10.1007/bf00355060;
RA Boer P.H., Gray M.W.;
RT "Short dispersed repeats localized in spacer regions of Chlamydomonas
RT reinhardtii mitochondrial DNA.";
RL Curr. Genet. 19:309-312(1991).
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:P00163}.
CC -!- COFACTOR:
CC Name=heme b; Xref=ChEBI:CHEBI:60344;
CC Evidence={ECO:0000250|UniProtKB:P00163};
CC Note=Binds 2 heme b groups non-covalently.
CC {ECO:0000250|UniProtKB:P00163};
CC -!- SUBUNIT: The main subunits of complex b-c1 are: cytochrome b,
CC cytochrome c1 and the Rieske protein. {ECO:0000250}.
CC -!- SUBCELLULAR LOCATION: Mitochondrion inner membrane
CC {ECO:0000250|UniProtKB:P00163}; Multi-pass membrane protein
CC {ECO:0000250|UniProtKB:P00163}.
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 protein contains only eight transmembrane helices, not
CC nine as predicted by bioinformatics tools.
CC {ECO:0000250|UniProtKB:P00163}.
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DR EMBL; X66484; CAA47111.1; -; Genomic_DNA.
DR EMBL; X55305; CAA39011.1; -; Genomic_DNA.
DR EMBL; X52168; CAA36421.1; -; Genomic_DNA.
DR AlphaFoldDB; P23662; -.
DR SMR; P23662; -.
DR STRING; 3055.AAB93440; -.
DR eggNOG; KOG4663; Eukaryota.
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..381
FT /note="Cytochrome b"
FT /id="PRO_0000060782"
FT TRANSMEM 32..52
FT /note="Helical"
FT /evidence="ECO:0000250|UniProtKB:P00163"
FT TRANSMEM 76..98
FT /note="Helical"
FT /evidence="ECO:0000250|UniProtKB:P00163"
FT TRANSMEM 113..133
FT /note="Helical"
FT /evidence="ECO:0000250|UniProtKB:P00163"
FT TRANSMEM 179..199
FT /note="Helical"
FT /evidence="ECO:0000250|UniProtKB:P00163"
FT TRANSMEM 225..245
FT /note="Helical"
FT /evidence="ECO:0000250|UniProtKB:P00163"
FT TRANSMEM 289..309
FT /note="Helical"
FT /evidence="ECO:0000250|UniProtKB:P00163"
FT TRANSMEM 318..338
FT /note="Helical"
FT /evidence="ECO:0000250|UniProtKB:P00163"
FT TRANSMEM 345..365
FT /note="Helical"
FT /evidence="ECO:0000250|UniProtKB:P00163"
FT BINDING 82
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:P00163"
FT BINDING 96
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:P00163"
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:P00163"
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:P00163"
FT BINDING 202
FT /ligand="a ubiquinone"
FT /ligand_id="ChEBI:CHEBI:16389"
FT /evidence="ECO:0000250|UniProtKB:P00157"
FT VARIANT 317
FT /note="I -> T (in strain: CC-1373)"
FT CONFLICT 232..242
FT /note="GALFLALVFSI -> VLCSWLLCSAF (in Ref. 3; CAA36421)"
FT /evidence="ECO:0000305"
SQ SEQUENCE 381 AA; 42331 MW; 06BD583D601B6715 CRC64;
MRMHNKIQLL SVLNTHLVAY PTPMNLNYSW NGGSLAGMML ASQMLTGILL AMHYVGHVDY
AFASVQHLMT DVPSGMILRY AHANGASLFF IVVYLHVLRG MYYGSGAQPR EIVWISGVVI
LLVMIITAFI GYVLPWGQMS FWGATVITSL ATAIPVVGKH IMYWLWGGFS VDNPTLNRFY
SFHYTLPFIL AGLSVFHIAA LHQYGSTNPL GVNSQSSLIS FGSYFGAKDL VGALFLALVF
SILVFFYPDL LGHPDNLIPA NPYSTPQHIV PEWYFLWVYA ILRSIPNKAM GVLAIGLVFA
SLFAMPFIGL GGGKFRIITE WLYWTFLADV LLLTWLGGNE ITPITSFVGQ CCTAYLFFYL
LVCQPLVGYL ETQFAHGTQT N
