DOXA_ACIAM
ID DOXA_ACIAM Reviewed; 168 AA.
AC P97224;
DT 05-SEP-2012, integrated into UniProtKB/Swiss-Prot.
DT 01-MAY-1997, sequence version 1.
DT 03-AUG-2022, entry version 51.
DE RecName: Full=Thiosulfate dehydrogenase [quinone] small subunit;
DE EC=1.8.5.2;
DE AltName: Full=Terminal oxidase subunit II;
DE AltName: Full=Thiosulfate:quinone oxidoreductase;
DE Short=TQO;
GN Name=doxA;
OS Acidianus ambivalens (Desulfurolobus ambivalens).
OC Archaea; Crenarchaeota; Thermoprotei; Sulfolobales; Sulfolobaceae;
OC Acidianus.
OX NCBI_TaxID=2283;
RN [1]
RP NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC STRAIN=Lei 10 / DSM 3772 / JCM 9191;
RX PubMed=9023221; DOI=10.1128/jb.179.4.1344-1353.1997;
RA Purschke W.G., Schmidt C.L., Petersen A., Schafer G.;
RT "The terminal quinol oxidase of the hyperthermophilic archaeon Acidianus
RT ambivalens exhibits a novel subunit structure and gene organization.";
RL J. Bacteriol. 179:1344-1353(1997).
RN [2]
RP FUNCTION, CATALYTIC ACTIVITY, ACTIVITY REGULATION, BIOPHYSICOCHEMICAL
RP PROPERTIES, SUBUNIT, GLYCOSYLATION, AND SUBCELLULAR LOCATION.
RX PubMed=15306018; DOI=10.1111/j.1365-2958.2004.04193.x;
RA Muller F.H., Bandeiras T.M., Urich T., Teixeira M., Gomes C.M., Kletzin A.;
RT "Coupling of the pathway of sulphur oxidation to dioxygen reduction:
RT characterization of a novel membrane-bound thiosulphate:quinone
RT oxidoreductase.";
RL Mol. Microbiol. 53:1147-1160(2004).
CC -!- FUNCTION: TQO plays a role in sulfur oxidation and is proposed to
CC couple sulfur oxidation to dioxygen reduction; caldariellaquinone or
CC sulfolobus quinone seem to serve to transfer electrons to the electron
CC transport chain terminal oxidase formed by DoxBCE.
CC {ECO:0000269|PubMed:15306018}.
CC -!- CATALYTIC ACTIVITY:
CC Reaction=6-decylubiquinone + 2 thiosulfate = 6-decylubiquinol +
CC tetrathionate; Xref=Rhea:RHEA:10936, ChEBI:CHEBI:15226,
CC ChEBI:CHEBI:33542, ChEBI:CHEBI:52020, ChEBI:CHEBI:52021; EC=1.8.5.2;
CC Evidence={ECO:0000269|PubMed:15306018};
CC -!- ACTIVITY REGULATION: Inhibited by sulfite, metabisulfite and dithonite.
CC {ECO:0000269|PubMed:15306018}.
CC -!- BIOPHYSICOCHEMICAL PROPERTIES:
CC Kinetic parameters:
CC KM=3.4 mM for thiosulfate (with ferrocyanide as electron acceptor)
CC {ECO:0000269|PubMed:15306018};
CC KM=5.87 mM for thiosulfate (with decylubiquinol as electron acceptor)
CC {ECO:0000269|PubMed:15306018};
CC Vmax=78 umol/min/mg enzyme with thiosulfate as substrate
CC {ECO:0000269|PubMed:15306018};
CC Note=KM values measured using the TQO doxDA complex.;
CC pH dependence:
CC Optimum pH is around 5, pH range of activity is different in tested
CC buffers. {ECO:0000269|PubMed:15306018};
CC Temperature dependence:
CC Increasing activity in the range between 20 and 92 degrees Celsius.
CC {ECO:0000269|PubMed:15306018};
CC -!- SUBUNIT: Heterodimer of a large and a small subunit in a 2:2
CC stoichiometry (Probable). TQO may associate with the terminal oxidase
CC formed by doxBCE. {ECO:0000269|PubMed:15306018, ECO:0000305}.
CC -!- SUBCELLULAR LOCATION: Cell membrane {ECO:0000269|PubMed:15306018};
CC Single-pass membrane protein {ECO:0000269|PubMed:15306018}.
CC -!- PTM: The N-terminus is blocked.
CC -!- PTM: Glycosylated. {ECO:0000269|PubMed:15306018}.
CC -!- CAUTION: The thiosulfate dehydrogenase [quinone] subunits have
CC originally been described as components of the aa3-type terminal
CC oxidase. {ECO:0000305|PubMed:9023221}.
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; Y08730; CAA69987.1; -; Genomic_DNA.
DR EMBL; Y09614; CAA70828.1; -; Genomic_DNA.
DR AlphaFoldDB; P97224; -.
DR TCDB; 3.D.4.9.1; the proton-translocating cytochrome oxidase (cox) superfamily.
DR BioCyc; MetaCyc:MON-12418; -.
DR BRENDA; 1.8.5.2; 86.
DR GO; GO:0016021; C:integral component of membrane; IEA:UniProtKB-KW.
DR GO; GO:0016020; C:membrane; IDA:UniProtKB.
DR GO; GO:1990204; C:oxidoreductase complex; IDA:UniProtKB.
DR GO; GO:0005886; C:plasma membrane; IEA:UniProtKB-SubCell.
DR GO; GO:0070469; C:respirasome; IEA:UniProtKB-KW.
DR GO; GO:0048038; F:quinone binding; IEA:UniProtKB-KW.
DR GO; GO:0043831; F:thiosulfate dehydrogenase (quinone) activity; IEA:UniProtKB-EC.
DR InterPro; IPR011636; DoxA.
DR Pfam; PF07680; DoxA; 1.
PE 1: Evidence at protein level;
KW Cell membrane; Electron transport; Glycoprotein; Membrane; Oxidoreductase;
KW Quinone; Respiratory chain; Transmembrane; Transmembrane helix; Transport.
FT CHAIN 1..168
FT /note="Thiosulfate dehydrogenase [quinone] small subunit"
FT /id="PRO_0000418548"
FT TRANSMEM 6..26
FT /note="Helical"
FT /evidence="ECO:0000255"
SQ SEQUENCE 168 AA; 18757 MW; EC332C5FF251A5FD CRC64;
MERVTIIGII FAILVVGWIL ATGQWAYGNV VGPLVNHSKI PLLKITYVSA YENAKGTYLI
LNITDCCGPD AYPASAPIME IYNSTWHVFL YSYNISNDTV KVIQAPWNEN KKDYTNWYSG
FVVILGSEAQ FQLQLPFHLS PGTYHIKLYT PAVSSKVLAK QTATFTIS
