CYB_ASCSU
ID CYB_ASCSU Reviewed; 365 AA.
AC P24878;
DT 01-MAR-1992, integrated into UniProtKB/Swiss-Prot.
DT 01-FEB-1996, sequence version 2.
DT 03-AUG-2022, entry version 96.
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 Ascaris suum (Pig roundworm) (Ascaris lumbricoides).
OG Mitochondrion.
OC Eukaryota; Metazoa; Ecdysozoa; Nematoda; Chromadorea; Rhabditida;
OC Spirurina; Ascaridomorpha; Ascaridoidea; Ascarididae; Ascaris.
OX NCBI_TaxID=6253;
RN [1]
RP NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC TISSUE=Body wall muscle, and Egg;
RX PubMed=1551572; DOI=10.1093/genetics/130.3.471;
RA Okimoto R., Macfarlane J.L., Clary D.O., Wolstenholme D.R.;
RT "The mitochondrial genomes of two nematodes, Caenorhabditis elegans and
RT Ascaris suum.";
RL Genetics 130:471-498(1992).
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 main subunits of complex b-c1 are: cytochrome b,
CC cytochrome c1 and the Rieske protein. {ECO:0000250|UniProtKB:P00157}.
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 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; X54253; CAA38168.1; -; Genomic_DNA.
DR PIR; S26019; S26019.
DR RefSeq; NP_006946.1; NC_001327.1.
DR AlphaFoldDB; P24878; -.
DR SMR; P24878; -.
DR GeneID; 807673; -.
DR CTD; 4519; -.
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 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; IPR016174; Di-haem_cyt_TM.
DR Pfam; PF00032; Cytochrom_B_C; 1.
DR Pfam; PF00033; Cytochrome_B; 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..365
FT /note="Cytochrome b"
FT /id="PRO_0000060643"
FT TRANSMEM 25..45
FT /note="Helical"
FT /evidence="ECO:0000250|UniProtKB:P00163"
FT TRANSMEM 69..91
FT /note="Helical"
FT /evidence="ECO:0000250|UniProtKB:P00163"
FT TRANSMEM 104..124
FT /note="Helical"
FT /evidence="ECO:0000250|UniProtKB:P00163"
FT TRANSMEM 170..190
FT /note="Helical"
FT /evidence="ECO:0000250|UniProtKB:P00163"
FT TRANSMEM 216..235
FT /note="Helical"
FT /evidence="ECO:0000250|UniProtKB:P00163"
FT TRANSMEM 279..299
FT /note="Helical"
FT /evidence="ECO:0000255"
FT TRANSMEM 311..331
FT /note="Helical"
FT /evidence="ECO:0000255"
FT TRANSMEM 335..355
FT /note="Helical"
FT /evidence="ECO:0000255"
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 365 AA; 42361 MW; 4851779811B2CA8D CRC64;
MKLDFVNSMV VSLPSSKVLT YGWNFGSMLG MVLGFQILTG TFLAFYYSND GALAFLSVQY
IMYEVNFGWI FRVLHFNGAS LFFIFLYLHL FKGLFFMSYR LKKVWVSGIV ILLLVMMEAF
MGYVLVWAQM SFWASVVITS LLSVIPVWGF AIVTWIWSGF TVSSATLKFF FVLHFLVPWG
LLLLVLLHLV FLHETGSTSK LYCHGDYDKV CFYPEYWVKD FLNVVVWFVF IFFSLGYPFL
LGDPEMFIES DPMMSPVHIV PEWYFLFAYA ILRAIPNKVL GVVSLFASIL VLVVFVLVNN
YVSVMSKLNK FLVFVFIFVL VVLSWLGQCL VEDPFVFLSM VFSFLYFFVI FLLFLVYYFA
GRVFM
