SQRD_ACIAM
ID SQRD_ACIAM Reviewed; 409 AA.
AC Q7ZAG8;
DT 29-OCT-2014, integrated into UniProtKB/Swiss-Prot.
DT 01-OCT-2003, sequence version 1.
DT 03-AUG-2022, entry version 62.
DE RecName: Full=Sulfide-quinone reductase {ECO:0000305};
DE Short=SQR;
DE EC=1.8.5.4 {ECO:0000269|PubMed:19438211};
DE AltName: Full=Sulfide:quinone oxidoreductase {ECO:0000303|PubMed:19438211};
GN Name=sqr {ECO:0000305}; Synonyms=noxA {ECO:0000303|PubMed:12417325};
OS Acidianus ambivalens (Desulfurolobus ambivalens).
OC Archaea; Crenarchaeota; Thermoprotei; Sulfolobales; Sulfolobaceae;
OC Acidianus.
OX NCBI_TaxID=2283 {ECO:0000312|EMBL:CAD33806.1};
RN [1] {ECO:0000312|EMBL:CAD33806.1}
RP NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC STRAIN=Lei 10 / DSM 3772 / JCM 9191 {ECO:0000312|EMBL:CAD33806.1};
RX PubMed=12417325; DOI=10.1016/s0014-5793(02)03514-7;
RA Bandeiras T.M., Salgueiro C., Kletzin A., Gomes C.M., Teixeira M.;
RT "Acidianus ambivalens type-II NADH dehydrogenase: genetic characterisation
RT and identification of the flavin moiety as FMN.";
RL FEBS Lett. 531:273-277(2002).
RN [2]
RP X-RAY CRYSTALLOGRAPHY (2.57 ANGSTROMS) IN COMPLEX WITH FAD, FUNCTION,
RP CATALYTIC ACTIVITY, ACTIVE SITE, ACTIVITY REGULATION, COFACTOR, DISULFIDE
RP BOND, SUBCELLULAR LOCATION, SUBUNIT, AND BIOPHYSICOCHEMICAL PROPERTIES.
RX PubMed=19438211; DOI=10.1021/bi9003827;
RA Brito J.A., Sousa F.L., Stelter M., Bandeiras T.M., Vonrhein C.,
RA Teixeira M., Pereira M.M., Archer M.;
RT "Structural and functional insights into sulfide:quinone oxidoreductase.";
RL Biochemistry 48:5613-5622(2009).
CC -!- FUNCTION: Catalyzes the oxidation of sulfides, such as hydrogen
CC sulfide, with the help of a quinone. Has the highest activity with
CC caldariella quinone and decylubiquinone, and lower activity with
CC naphtoquinones. Consecutive reaction cycles lead to the accumulation of
CC a polysulfide product on the active site Cys residues; these products
CC are released when they exceed a critical length, typically as
CC cyclooctasulfur. {ECO:0000269|PubMed:19438211}.
CC -!- CATALYTIC ACTIVITY:
CC Reaction=n a quinone + n H(+) + n hydrogen sulfide = n a quinol + n
CC sulfur; Xref=Rhea:RHEA:30239, ChEBI:CHEBI:15378, ChEBI:CHEBI:24646,
CC ChEBI:CHEBI:26833, ChEBI:CHEBI:29919, ChEBI:CHEBI:132124; EC=1.8.5.4;
CC Evidence={ECO:0000269|PubMed:19438211};
CC -!- COFACTOR:
CC Name=FAD; Xref=ChEBI:CHEBI:57692;
CC Evidence={ECO:0000269|PubMed:19438211};
CC Note=Binds 1 FAD per subunit. {ECO:0000269|PubMed:19438211};
CC -!- ACTIVITY REGULATION: Inhibited by the quinone analog 2-heptyl-4-
CC hydroxyquinolone N-oxide (HQNO). Inactivated by iodoacetamide
CC treatment. Inhibited by KCN. {ECO:0000269|PubMed:19438211}.
CC -!- BIOPHYSICOCHEMICAL PROPERTIES:
CC pH dependence:
CC Optimum pH is about 6. {ECO:0000269|PubMed:19438211};
CC Temperature dependence:
CC Optimum temperature is above 70 degrees Celsius.
CC {ECO:0000269|PubMed:19438211};
CC -!- SUBUNIT: Monomer. {ECO:0000269|PubMed:19438211}.
CC -!- SUBCELLULAR LOCATION: Membrane {ECO:0000303|PubMed:19438211};
CC Peripheral membrane protein {ECO:0000303|PubMed:19438211}.
CC -!- SIMILARITY: Belongs to the SQRD family. {ECO:0000305}.
CC -!- CAUTION: Was originally identified as FMN-containing NADH dehydrogenase
CC (PubMed:12417325), based on the NADH oxidase activity of the C-
CC terminally truncated protein. Was then shown to function as
CC sulfide:quinone reductase. The full-length protein does not have NADH
CC oxidase activity (PubMed:19438211). {ECO:0000269|PubMed:19438211,
CC ECO:0000305}.
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DR EMBL; AJ489504; CAD33806.1; -; Genomic_DNA.
DR PDB; 3H8I; X-ray; 2.65 A; A/B=1-409.
DR PDB; 3H8L; X-ray; 2.57 A; A/B=1-409.
DR PDBsum; 3H8I; -.
DR PDBsum; 3H8L; -.
DR AlphaFoldDB; Q7ZAG8; -.
DR SMR; Q7ZAG8; -.
DR EvolutionaryTrace; Q7ZAG8; -.
DR GO; GO:0016020; C:membrane; IEA:UniProtKB-SubCell.
DR GO; GO:0000166; F:nucleotide binding; IEA:UniProtKB-KW.
DR GO; GO:0048038; F:quinone binding; IEA:UniProtKB-KW.
DR GO; GO:0070224; F:sulfide:quinone oxidoreductase activity; IEA:RHEA.
DR Gene3D; 3.50.50.60; -; 2.
DR InterPro; IPR036188; FAD/NAD-bd_sf.
DR InterPro; IPR023753; FAD/NAD-binding_dom.
DR Pfam; PF07992; Pyr_redox_2; 2.
DR SUPFAM; SSF51905; SSF51905; 2.
PE 1: Evidence at protein level;
KW 3D-structure; FAD; Flavoprotein; Membrane; Nucleotide-binding;
KW Oxidoreductase; Quinone.
FT CHAIN 1..409
FT /note="Sulfide-quinone reductase"
FT /id="PRO_0000430826"
FT ACT_SITE 178
FT /note="Cysteine persulfide intermediate"
FT /evidence="ECO:0000269|PubMed:19438211"
FT ACT_SITE 350
FT /note="Cysteine persulfide intermediate"
FT /evidence="ECO:0000269|PubMed:19438211"
FT BINDING 8..12
FT /ligand="FAD"
FT /ligand_id="ChEBI:CHEBI:57692"
FT /evidence="ECO:0000269|PubMed:19438211"
FT BINDING 34..35
FT /ligand="FAD"
FT /ligand_id="ChEBI:CHEBI:57692"
FT /evidence="ECO:0000269|PubMed:19438211"
FT BINDING 129
FT /ligand="FAD"
FT /ligand_id="ChEBI:CHEBI:57692"
FT /evidence="ECO:0000269|PubMed:19438211"
FT BINDING 271
FT /ligand="FAD"
FT /ligand_id="ChEBI:CHEBI:57692"
FT /evidence="ECO:0000269|PubMed:19438211"
FT BINDING 307
FT /ligand="FAD"
FT /ligand_id="ChEBI:CHEBI:57692"
FT /evidence="ECO:0000269|PubMed:19438211"
FT BINDING 317
FT /ligand="FAD"
FT /ligand_id="ChEBI:CHEBI:57692"
FT /evidence="ECO:0000269|PubMed:19438211"
FT STRAND 3..7
FT /evidence="ECO:0007829|PDB:3H8L"
FT HELIX 11..24
FT /evidence="ECO:0007829|PDB:3H8L"
FT HELIX 25..27
FT /evidence="ECO:0007829|PDB:3H8L"
FT STRAND 28..41
FT /evidence="ECO:0007829|PDB:3H8L"
FT STRAND 58..61
FT /evidence="ECO:0007829|PDB:3H8L"
FT HELIX 62..65
FT /evidence="ECO:0007829|PDB:3H8L"
FT HELIX 67..69
FT /evidence="ECO:0007829|PDB:3H8L"
FT STRAND 72..75
FT /evidence="ECO:0007829|PDB:3H8L"
FT STRAND 77..82
FT /evidence="ECO:0007829|PDB:3H8L"
FT TURN 83..86
FT /evidence="ECO:0007829|PDB:3H8L"
FT STRAND 87..91
FT /evidence="ECO:0007829|PDB:3H8L"
FT STRAND 97..101
FT /evidence="ECO:0007829|PDB:3H8L"
FT STRAND 103..107
FT /evidence="ECO:0007829|PDB:3H8L"
FT HELIX 115..117
FT /evidence="ECO:0007829|PDB:3H8L"
FT HELIX 121..124
FT /evidence="ECO:0007829|PDB:3H8L"
FT STRAND 126..130
FT /evidence="ECO:0007829|PDB:3H8L"
FT HELIX 133..143
FT /evidence="ECO:0007829|PDB:3H8L"
FT STRAND 146..153
FT /evidence="ECO:0007829|PDB:3H8L"
FT HELIX 180..194
FT /evidence="ECO:0007829|PDB:3H8L"
FT TURN 195..197
FT /evidence="ECO:0007829|PDB:3H8L"
FT TURN 199..201
FT /evidence="ECO:0007829|PDB:3H8L"
FT STRAND 202..207
FT /evidence="ECO:0007829|PDB:3H8L"
FT STRAND 209..213
FT /evidence="ECO:0007829|PDB:3H8L"
FT HELIX 218..231
FT /evidence="ECO:0007829|PDB:3H8L"
FT STRAND 234..236
FT /evidence="ECO:0007829|PDB:3H8L"
FT STRAND 241..244
FT /evidence="ECO:0007829|PDB:3H8L"
FT STRAND 246..251
FT /evidence="ECO:0007829|PDB:3H8L"
FT STRAND 256..258
FT /evidence="ECO:0007829|PDB:3H8L"
FT STRAND 260..265
FT /evidence="ECO:0007829|PDB:3H8L"
FT HELIX 272..275
FT /evidence="ECO:0007829|PDB:3H8L"
FT HELIX 279..281
FT /evidence="ECO:0007829|PDB:3H8L"
FT STRAND 294..298
FT /evidence="ECO:0007829|PDB:3H8L"
FT STRAND 302..304
FT /evidence="ECO:0007829|PDB:3H8L"
FT HELIX 306..308
FT /evidence="ECO:0007829|PDB:3H8L"
FT HELIX 317..334
FT /evidence="ECO:0007829|PDB:3H8L"
FT HELIX 351..353
FT /evidence="ECO:0007829|PDB:3H8L"
SQ SEQUENCE 409 AA; 45152 MW; 2E5BC25064F47F21 CRC64;
MTKVLVLGGR FGALTAAYTL KRLVGSKADV KVINKSRFSY FRPALPHVAI GVRDVDELKV
DLSEALPEKG IQFQEGTVEK IDAKSSMVYY TKPDGSMAEE EYDYVIVGIG AHLATELVKG
WDKYGYSVCE PEFATKLREK LESFQGGNIA IGSGPFYQGH NPKPKVPENF VPNADSACEG
PVFEMSLMLH GYFKKKGMLD KVHVTVFSPG EYLSDLSPNS RKAVASIYNQ LGIKLVHNFK
IKEIREHEIV DEKGNTIPAD ITILLPPYTG NPALKNSTPD LVDDGGFIPT DLNMVSIKYD
NVYAVGDANS MTVPKLGYLA VMTGRIAAQH LANRLGVPTK VDKYYPTIMC VADNPYEGYA
VSVKDDTWYG GTVSIADPAA VNHLKKELFT KYYMWTKGDM ALEKFLASW
