CYB_PARTE
ID CYB_PARTE Reviewed; 391 AA.
AC P15585;
DT 01-APR-1990, integrated into UniProtKB/Swiss-Prot.
DT 01-APR-1990, sequence version 1.
DT 03-AUG-2022, entry version 95.
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 Paramecium tetraurelia.
OG Mitochondrion.
OC Eukaryota; Sar; Alveolata; Ciliophora; Intramacronucleata;
OC Oligohymenophorea; Peniculida; Parameciidae; Paramecium.
OX NCBI_TaxID=5888;
RN [1]
RP NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC STRAIN=Stock 51;
RX PubMed=2308823; DOI=10.1093/nar/18.1.173;
RA Pritchard A.E., Seilhamer J.J., Mahalingam R., Sable C.L., Venuti S.E.,
RA Cummings D.J.;
RT "Nucleotide sequence of the mitochondrial genome of Paramecium.";
RL Nucleic Acids Res. 18:173-180(1990).
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:PRU00968}.
CC -!- CAUTION: The protein contains an even number of transmembrane helices,
CC fewer than predicted by bioinformatics tools.
CC {ECO:0000250|UniProtKB:P00163}.
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; X15917; CAA34052.1; -; Genomic_DNA.
DR PIR; S07743; S07743.
DR AlphaFoldDB; P15585; -.
DR SMR; P15585; -.
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:0070469; C:respirasome; IEA:UniProtKB-KW.
DR GO; GO:0009055; F:electron transfer activity; IEA:InterPro.
DR GO; GO:0046872; F:metal ion binding; IEA:UniProtKB-KW.
DR GO; GO:0022904; P:respiratory electron transport chain; IEA:InterPro.
DR Gene3D; 1.20.810.10; -; 1.
DR InterPro; IPR005797; Cyt_b/b6_N.
DR InterPro; IPR027387; Cytb/b6-like_sf.
DR InterPro; IPR016174; Di-haem_cyt_TM.
DR Pfam; PF00033; Cytochrome_B; 1.
DR SUPFAM; SSF81342; SSF81342; 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..391
FT /note="Cytochrome b"
FT /id="PRO_0000061358"
FT TRANSMEM 22..42
FT /note="Helical"
FT /evidence="ECO:0000250|UniProtKB:P00163"
FT TRANSMEM 67..88
FT /note="Helical"
FT /evidence="ECO:0000250|UniProtKB:P00163"
FT TRANSMEM 103..123
FT /note="Helical"
FT /evidence="ECO:0000250|UniProtKB:P00163"
FT TRANSMEM 169..189
FT /note="Helical"
FT /evidence="ECO:0000250|UniProtKB:P00163"
FT TRANSMEM 213..233
FT /note="Helical"
FT /evidence="ECO:0000250|UniProtKB:P00163"
FT TRANSMEM 275..295
FT /note="Helical"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00968"
FT TRANSMEM 341..361
FT /note="Helical"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00968"
FT TRANSMEM 370..390
FT /note="Helical"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00968"
FT BINDING 72
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 86
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 173
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 187
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 192
FT /ligand="a ubiquinone"
FT /ligand_id="ChEBI:CHEBI:16389"
FT /evidence="ECO:0000250|UniProtKB:P00157"
SQ SEQUENCE 391 AA; 46044 MW; FCF34BAC4A543C25 CRC64;
MLNIFNYFKN LRVSFHEVFS LFGFFTFMTI IVQLVSGTML AFSSVPEPML IPTVRDEEDI
EDLYTDDFFW LHERGVDLIF IFSYFHLLRK LYLNVFDLET EASWKSGVFS FLVFQVVVFF
GLVLCCTHLS EITLTIAANI FHTFFMFKGK AYWFLFTDKQ LNTDTLIRLA YAHYVSAFYL
SFLGLLHGID IHYDWKNEPF YDGLSSEMLW WDEALSNELT NFFVLLVFIT LAFFLLFEEP
EALSYEIFMW GDIGLSTDVR FYGVAPHWYF RPFMAWLIAC PFHKTGIFGL LFFFVTLYYQ
PNLHGVSDQN SYGKKTLTIS STVLAKKNTA TPFSISIDSN LYHQITYFFF IMCCLYTPSF
LPYGRFFNQI GGNWGFLFSY FYVFCYLAFT D
