QCRB_STRLI
ID QCRB_STRLI Reviewed; 549 AA.
AC Q9ZFB6;
DT 30-MAY-2000, integrated into UniProtKB/Swiss-Prot.
DT 01-MAY-1999, sequence version 1.
DT 03-AUG-2022, entry version 88.
DE RecName: Full=Cytochrome bc1 complex cytochrome b subunit;
DE EC=7.1.1.8 {ECO:0000250|UniProtKB:P9WP37};
DE AltName: Full=Cytochrome bc1 reductase complex subunit QcrB;
DE AltName: Full=Ubiquinol--cytochrome c reductase cytochrome b subunit;
GN Name=qcrB;
OS Streptomyces lividans.
OC Bacteria; Actinobacteria; Streptomycetales; Streptomycetaceae;
OC Streptomyces.
OX NCBI_TaxID=1916;
RN [1]
RP NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC STRAIN=TK21;
RA Parro V., Mellado R.P.;
RT "Cytochrome b of Streptomyces lividans.";
RL Submitted (NOV-1998) to the EMBL/GenBank/DDBJ databases.
CC -!- FUNCTION: Cytochrome b subunit of the cytochrome bc1 complex, an
CC essential component of the respiratory electron transport chain
CC required for ATP synthesis. The bc1 complex catalyzes the oxidation of
CC ubiquinol and the reduction of cytochrome c in the respiratory chain.
CC The bc1 complex operates through a Q-cycle mechanism that couples
CC electron transfer to generation of the proton gradient that drives ATP
CC synthesis. The cytochrome b subunit contains two ubiquinol reactive
CC sites: the oxidation (QP) site and the reduction (QN) site.
CC {ECO:0000250|UniProtKB:P9WP37}.
CC -!- CATALYTIC ACTIVITY:
CC Reaction=a quinol + 2 Fe(III)-[cytochrome c](out) = a quinone + 2
CC Fe(II)-[cytochrome c](out) + 2 H(+)(out); Xref=Rhea:RHEA:11484,
CC Rhea:RHEA-COMP:10350, Rhea:RHEA-COMP:14399, ChEBI:CHEBI:15378,
CC ChEBI:CHEBI:24646, ChEBI:CHEBI:29033, ChEBI:CHEBI:29034,
CC ChEBI:CHEBI:132124; EC=7.1.1.8;
CC Evidence={ECO:0000250|UniProtKB:P9WP37};
CC -!- COFACTOR:
CC Name=heme; Xref=ChEBI:CHEBI:30413;
CC Evidence={ECO:0000250|UniProtKB:P00163};
CC Note=Binds 2 heme groups non-covalently per subunit.
CC {ECO:0000250|UniProtKB:P00163};
CC -!- SUBUNIT: The cytochrome bc1 complex is composed of a cytochrome b
CC (QcrB), the Rieske iron-sulfur protein (QcrA) and a diheme cytochrome c
CC (QcrC) subunit. {ECO:0000250|UniProtKB:P9WP37}.
CC -!- SUBCELLULAR LOCATION: Cell membrane {ECO:0000255}; Multi-pass membrane
CC protein {ECO:0000255}.
CC -!- SIMILARITY: Belongs to the cytochrome b family. {ECO:0000255|PROSITE-
CC ProRule:PRU00968}.
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; AF107888; AAD04933.1; -; Genomic_DNA.
DR AlphaFoldDB; Q9ZFB6; -.
DR SMR; Q9ZFB6; -.
DR GO; GO:0016021; C:integral component of membrane; IEA:UniProtKB-KW.
DR GO; GO:0005886; C:plasma membrane; IEA:UniProtKB-SubCell.
DR GO; GO:0070469; C:respirasome; IEA:UniProtKB-KW.
DR GO; GO:0046872; F:metal ion binding; IEA:UniProtKB-KW.
DR GO; GO:0008121; F:ubiquinol-cytochrome-c reductase activity; IEA:UniProtKB-EC.
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; PF13631; Cytochrom_B_N_2; 1.
DR SUPFAM; SSF81342; SSF81342; 1.
DR PROSITE; PS51002; CYTB_NTER; 1.
PE 3: Inferred from homology;
KW Cell membrane; Electron transport; Heme; Iron; Membrane; Metal-binding;
KW Respiratory chain; Translocase; Transmembrane; Transmembrane helix;
KW Transport.
FT CHAIN 1..549
FT /note="Cytochrome bc1 complex cytochrome b subunit"
FT /id="PRO_0000061929"
FT TRANSMEM 54..74
FT /note="Helical"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00968"
FT TRANSMEM 122..142
FT /note="Helical"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00968"
FT TRANSMEM 150..170
FT /note="Helical"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00968"
FT TRANSMEM 182..202
FT /note="Helical"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00968"
FT TRANSMEM 220..240
FT /note="Helical"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00968"
FT TRANSMEM 269..289
FT /note="Helical"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00968"
FT TRANSMEM 334..354
FT /note="Helical"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00968"
FT TRANSMEM 389..409
FT /note="Helical"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00968"
FT TRANSMEM 417..437
FT /note="Helical"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00968"
FT BINDING 118
FT /ligand="heme"
FT /ligand_id="ChEBI:CHEBI:30413"
FT /ligand_label="1"
FT /ligand_part="Fe"
FT /ligand_part_id="ChEBI:CHEBI:18248"
FT /note="axial binding residue"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00968"
FT BINDING 132
FT /ligand="heme"
FT /ligand_id="ChEBI:CHEBI:30413"
FT /ligand_label="2"
FT /ligand_part="Fe"
FT /ligand_part_id="ChEBI:CHEBI:18248"
FT /note="axial binding residue"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00968"
FT BINDING 219
FT /ligand="heme"
FT /ligand_id="ChEBI:CHEBI:30413"
FT /ligand_label="1"
FT /ligand_part="Fe"
FT /ligand_part_id="ChEBI:CHEBI:18248"
FT /note="axial binding residue"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00968"
FT BINDING 234
FT /ligand="heme"
FT /ligand_id="ChEBI:CHEBI:30413"
FT /ligand_label="2"
FT /ligand_part="Fe"
FT /ligand_part_id="ChEBI:CHEBI:18248"
FT /note="axial binding residue"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00968"
SQ SEQUENCE 549 AA; 61203 MW; 36B6C7B6B120CBE4 CRC64;
MSTAANEPSR SRGKAPAGER VADWADGRLG IYSLAKANMR KIFPDHWSFM LGEVCLYSFI
IIILTGVYLT LFFHPSMAEV EYHGSYVPLQ GQMMSEAYAS TLDISFDVRG GLLIRQIHHW
AALIFLAGMF VHMMRVFFTG AFRKPREVNW LFGFLLLVLG MFTGFTGYSL PDDLLSGTGI
RFMEGAILSV PIVGTYISFF LFGGEFPGHD FVSRFYSIHI LLLPGIMLGL LVGHLILVFY
HKHTQFAGPG KTNKNVVGMP LLPVYTAKAG GFFFLVFGVI SVVSAIATIN PIWPSGPTGP
TRSPPAPSRL VLGFSEGLIR VMPGWEINAW GHTLVLGVFV PLLIFPLVLA AIAVYPFIES
WVTGYKREHY ILDRPLLDRP RNAPTRTAFG VAWLTVYFVL LIGGGNDLWA THFHLSINAI
TWFVRIAFFV GPVVAFIATK RICLGLQRRD KDKVLHGRES AIIKRLPHGE FIEVHEPISQ
EQLHTLTAHE QYKPAEIGPT VDENGVERKV SGTQKLRAKL SESYYGEESQ IPKPTVEEYK
EITSGHGHH
