CYB_TRYBO
ID CYB_TRYBO Reviewed; 372 AA.
AC Q33568; Q35988;
DT 01-NOV-1997, integrated into UniProtKB/Swiss-Prot.
DT 01-NOV-1997, sequence version 2.
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 Trypanoplasma borreli.
OG Mitochondrion.
OC Eukaryota; Discoba; Euglenozoa; Kinetoplastea; Metakinetoplastina;
OC Parabodonida; Trypanoplasma.
OX NCBI_TaxID=5710;
RN [1]
RP NUCLEOTIDE SEQUENCE [MRNA], AND RNA EDITING.
RC STRAIN=PG-JH;
RX PubMed=7969154; DOI=10.1128/mcb.14.12.8174-8182.1994;
RA Maslov D.A., Simpson L.;
RT "RNA editing and mitochondrial genomic organization in the cryptobiid
RT kinetoplastid protozoan Trypanoplasma borreli.";
RL Mol. Cell. Biol. 14:8174-8182(1994).
RN [2]
RP NUCLEOTIDE SEQUENCE [MRNA], AND RNA EDITING.
RC STRAIN=TT-JH;
RX PubMed=7525275; DOI=10.1002/j.1460-2075.1994.tb06838.x;
RA Lukes J., Arts G.J., van den Burg J., de Haan A., Opperdoes F., Sloof P.,
RA Benne R.;
RT "Novel pattern of editing regions in mitochondrial transcripts of the
RT cryptobiid Trypanoplasma borreli.";
RL EMBO J. 13:5086-5098(1994).
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 -!- RNA EDITING: Modified_positions=Not_applicable; Note=Some positions are
CC modified by RNA editing via nucleotide insertion or deletion.
CC {ECO:0000269|PubMed:7525275, ECO:0000269|PubMed:7969154};
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 an even number of transmembrane helices,
CC fewer than predicted by bioinformatics tools.
CC {ECO:0000250|UniProtKB:P00163}.
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DR EMBL; U14182; AAA65017.1; ALT_SEQ; mRNA.
DR EMBL; U11684; AAA73455.1; -; mRNA.
DR PIR; S52054; S52054.
DR AlphaFoldDB; Q33568; -.
DR SMR; Q33568; -.
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; 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 2: Evidence at transcript level;
KW Electron transport; Heme; Iron; Membrane; Metal-binding; Mitochondrion;
KW Mitochondrion inner membrane; Respiratory chain; RNA editing;
KW Transmembrane; Transmembrane helix; Transport; Ubiquinone.
FT CHAIN 1..372
FT /note="Cytochrome b"
FT /id="PRO_0000061691"
FT TRANSMEM 32..52
FT /note="Helical"
FT /evidence="ECO:0000250|UniProtKB:P00163"
FT TRANSMEM 77..99
FT /note="Helical"
FT /evidence="ECO:0000250|UniProtKB:P00163"
FT TRANSMEM 114..134
FT /note="Helical"
FT /evidence="ECO:0000250|UniProtKB:P00163"
FT TRANSMEM 180..200
FT /note="Helical"
FT /evidence="ECO:0000250|UniProtKB:P00163"
FT TRANSMEM 228..248
FT /note="Helical"
FT /evidence="ECO:0000250|UniProtKB:P00163"
FT TRANSMEM 297..317
FT /note="Helical"
FT /evidence="ECO:0000255"
FT TRANSMEM 330..350
FT /note="Helical"
FT /evidence="ECO:0000255"
FT TRANSMEM 351..371
FT /note="Helical"
FT /evidence="ECO:0000255"
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:P00163"
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:P00163"
FT BINDING 184
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 198
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 203
FT /ligand="a ubiquinone"
FT /ligand_id="ChEBI:CHEBI:16389"
FT /evidence="ECO:0000250|UniProtKB:P00157"
SQ SEQUENCE 372 AA; 44711 MW; DC4AF96804A0CDE6 CRC64;
MFFRLRFLVF FVLFRNLCCL LLSGDLFRVY GLGFNLGVMI ALQILVGICL SWFFFRCIIP
QNWIFTLLIH LEFDLGFIIR SLHIIFTSLL YFLLYIHIIK VIFLCLIFDS SMLVWFFGFL
IFIFILIIAF IGYTLPCTSM SYWGLTVFSN ILATIPLIGI YICQWIWCSE FINDFTLLKL
HSIHIFLPFV LLFLIGAHFF VLHYFLSSDG LLDRFPFYYE RFFFFLLYYL RDLFLIINIL
CFLIYYICIY WFFVFHEESW IIVDTLKTSD KILPEWFFLS FFGFLKSVPD KFMGLFLLFV
LCFALFLFIL NCILIFIYCR SSLLWMSLSL VLFYYLCVGG FLSLYVVLCF PLWMEIQFWV
LLLFCFIVCR LD
