CYB_PSEAU
ID CYB_PSEAU Reviewed; 372 AA.
AC Q9MLK4;
DT 01-JUN-2001, integrated into UniProtKB/Swiss-Prot.
DT 01-OCT-2000, sequence version 1.
DT 03-AUG-2022, entry version 90.
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 Pseudechis australis (Mulga snake) (King brown snake).
OG Mitochondrion.
OC Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi;
OC Lepidosauria; Squamata; Bifurcata; Unidentata; Episquamata; Toxicofera;
OC Serpentes; Colubroidea; Elapidae; Acanthophiinae; Pseudechis.
OX NCBI_TaxID=8670;
RN [1]
RP NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX PubMed=10764543; DOI=10.1006/mpev.1999.0725;
RA Slowinski J.B., Keogh J.S.;
RT "Phylogenetic relationships of elapid snakes based on cytochrome b mtDNA
RT sequences.";
RL Mol. Phylogenet. Evol. 15:157-164(2000).
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 3 respiratory subunits
CC (MT-CYB, CYC1 and UQCRFS1), 2 core proteins (UQCRC1 and UQCRC2) and
CC 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 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; AF217824; AAF37243.1; -; Genomic_DNA.
DR AlphaFoldDB; Q9MLK4; -.
DR SMR; Q9MLK4; -.
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..372
FT /note="Cytochrome b"
FT /id="PRO_0000061447"
FT TRANSMEM 25..45
FT /note="Helical"
FT /evidence="ECO:0000250|UniProtKB:P00157"
FT TRANSMEM 69..90
FT /note="Helical"
FT /evidence="ECO:0000250|UniProtKB:P00157"
FT TRANSMEM 105..125
FT /note="Helical"
FT /evidence="ECO:0000250|UniProtKB:P00157"
FT TRANSMEM 170..190
FT /note="Helical"
FT /evidence="ECO:0000250|UniProtKB:P00157"
FT TRANSMEM 218..238
FT /note="Helical"
FT /evidence="ECO:0000250|UniProtKB:P00157"
FT TRANSMEM 280..300
FT /note="Helical"
FT /evidence="ECO:0000250|UniProtKB:P00157"
FT TRANSMEM 312..332
FT /note="Helical"
FT /evidence="ECO:0000250|UniProtKB:P00157"
FT TRANSMEM 339..358
FT /note="Helical"
FT /evidence="ECO:0000250|UniProtKB:P00157"
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 372 AA; 42425 MW; 4B161F438F5DDF6C CRC64;
MPNQHTMASS NLLPVGSNIS TWWNFGSMLL TCLALQTLTG FFLAIHYTAN INLAFSSVTH
IVRDVPYGWI MQNMHAIGAS MFFICIYTHI ARGLYYGLYL NKEVWLSGTA LLIVLMATAF
FGYVLPWGQM SFWAATVITN LLTAIPYMGP KLTTWFWGGF SINDPTLTRF FALHFILPFL
IISLSSIHIM LLHNEGSNNP LGTNPDIDKI PFHPYHSYKD MFIITTMIAT LFIIMSFMPN
LFNDPENFSK ANPLVTPQHI KPEWYFLFAY GILRSIPNKL GGTMALLMSV LILTTMPFTH
TSHIRSLTFR PITQVVFWTF IATFITITWT ATKPVEPPFI LISQMASSMY FLFFIIHPLL
GWVENKIMMI NH
