ID   PA2T_OXYSC              Reviewed;          27 AA.
AC   Q7LZG2;
DT   31-MAY-2011, integrated into UniProtKB/Swiss-Prot.
DT   15-DEC-2003, sequence version 1.
DT   14-DEC-2022, entry version 69.
DE   RecName: Full=Phospholipase A2 taicatoxin;
DE            Short=TCX;
DE            Short=svPLA2;
DE            EC=3.1.1.4;
DE   AltName: Full=Phosphatidylcholine 2-acylhydrolase;
DE   Flags: Fragment;
OS   Oxyuranus scutellatus scutellatus (Australian taipan) (Coastal taipan).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi;
OC   Lepidosauria; Squamata; Bifurcata; Unidentata; Episquamata; Toxicofera;
OC   Serpentes; Colubroidea; Elapidae; Acanthophiinae; Oxyuranus.
OX   NCBI_TaxID=8667;
RN   [1]
RP   PROTEIN SEQUENCE, FUNCTION, SUBCELLULAR LOCATION, TISSUE SPECIFICITY, AND
RP   TOXIC DOSE.
RC   TISSUE=Venom;
RX   PubMed=1373076; DOI=10.1016/0167-4889(92)90178-e;
RA   Possani L.D., Mochca-Morales J., Amezcua J., Martin B.M., Prestipino G.,
RA   Nobile M.;
RT   "Anionic currents of chick sensory neurons are affected by a phospholipase
RT   A2 purified from the venom of the taipan snake.";
RL   Biochim. Biophys. Acta 1134:210-216(1992).
RN   [2]
RP   PROTEIN SEQUENCE, FUNCTION, SUBUNIT, SUBCELLULAR LOCATION, TISSUE
RP   SPECIFICITY, AND TOXIC DOSE.
RC   TISSUE=Venom;
RX   PubMed=1485334; DOI=10.1016/0041-0101(92)90511-3;
RA   Possani L.D., Martin B.M., Yatani A., Mochca-Morales J., Zamudio F.Z.,
RA   Gurrola G.B., Brown A.M.;
RT   "Isolation and physiological characterization of taicatoxin, a complex
RT   toxin with specific effects on calcium channels.";
RL   Toxicon 30:1343-1364(1992).
RN   [3]
RP   FUNCTION.
RX   PubMed=8901456; DOI=10.1007/bf00240032;
RA   Fantini E., Athias P., Tirosh R., Pinson A.;
RT   "Effect of TaiCatoxin (TCX) on the electrophysiological, mechanical and
RT   biochemical characteristics of spontaneously beating ventricular
RT   cardiomyocytes.";
RL   Mol. Cell. Biochem. 160:61-66(1996).
RN   [4]
RP   FUNCTION.
RX   PubMed=9242659; DOI=10.1074/jbc.272.32.19925;
RA   Doorty K.B., Bevan S., Wadsworth J.D.F., Strong P.N.;
RT   "A novel small conductance Ca2+-activated K+ channel blocker from Oxyuranus
RT   scutellatus taipan venom. Re-evaluation of taicatoxin as a selective Ca2+
RT   channel probe.";
RL   J. Biol. Chem. 272:19925-19930(1997).
RN   [5]
RP   FUNCTION.
RX   PubMed=15855042; DOI=10.1016/j.heares.2004.12.003;
RA   Su M.-C., Lee S.-Y., Tan C.-T., Su C.-C., Li S.-Y., Lin R.-H., Hung C.-C.,
RA   Lin M.-J.;
RT   "Taicatoxin inhibits the calcium-dependent slow motility of mammalian outer
RT   hair cells.";
RL   Hear. Res. 203:172-179(2005).
CC   -!- FUNCTION: Heterotrimer: blocks the voltage-dependent L-type calcium
CC       channels from the heart, and the small conductance calcium-activated
CC       potassium channels in the chromaffin cells and in the brain. Is very
CC       toxic to mice.
CC   -!- FUNCTION: Monomer: Snake venom phospholipase A2 (PLA2) that has
CC       neurotoxic activities. Voltage-dependently affects ionic currents in
CC       chick (Gallus domesticus) dorsal root ganglion cells. PLA2 catalyzes
CC       the calcium-dependent hydrolysis of the 2-acyl groups in 3-sn-
CC       phosphoglycerides.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=a 1,2-diacyl-sn-glycero-3-phosphocholine + H2O = a 1-acyl-sn-
CC         glycero-3-phosphocholine + a fatty acid + H(+); Xref=Rhea:RHEA:15801,
CC         ChEBI:CHEBI:15377, ChEBI:CHEBI:15378, ChEBI:CHEBI:28868,
CC         ChEBI:CHEBI:57643, ChEBI:CHEBI:58168; EC=3.1.1.4;
CC         Evidence={ECO:0000255|PROSITE-ProRule:PRU10035, ECO:0000255|PROSITE-
CC         ProRule:PRU10036};
CC   -!- COFACTOR:
CC       Name=Ca(2+); Xref=ChEBI:CHEBI:29108; Evidence={ECO:0000250};
CC       Note=Binds 1 Ca(2+) ion. {ECO:0000250};
CC   -!- SUBUNIT: Heterotrimer composed of an alpha-neurotoxin-like peptide of 8
CC       kDa (AC P0CJ35), this neurotoxic phospholipase of 16 kDa and a serine
CC       protease inhibitor of 7 kDa (AC B7S4N9) at an approximate stoichiometry
CC       of 1:1:4; non-covalently linked. {ECO:0000269|PubMed:1485334}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:1373076,
CC       ECO:0000269|PubMed:1485334}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC       {ECO:0000269|PubMed:1373076, ECO:0000269|PubMed:1485334}.
CC   -!- PTM: Contains 7 disulfide bonds. {ECO:0000250}.
CC   -!- TOXIC DOSE: Monomer: LD(50) is 500 ug/kg when injected into mice.
CC   -!- TOXIC DOSE: Heterotrimer: LD(50) is 50-100 ug/kg when injected into
CC       mice.
CC   -!- SIMILARITY: Belongs to the phospholipase A2 family. Group I subfamily.
CC       {ECO:0000305}.
CC   -!- WEB RESOURCE: Name=Wikipedia; Note=Taicatoxin entry;
CC       URL="https://en.wikipedia.org/wiki/Taicatoxin";
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DR   PIR; A34280; A34280.
DR   PIR; S21101; S21101.
DR   AlphaFoldDB; Q7LZG2; -.
DR   SMR; Q7LZG2; -.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0046872; F:metal ion binding; IEA:UniProtKB-KW.
DR   GO; GO:0004623; F:phospholipase A2 activity; IEA:UniProtKB-EC.
DR   GO; GO:0015459; F:potassium channel regulator activity; IEA:UniProtKB-KW.
DR   GO; GO:0090729; F:toxin activity; IEA:UniProtKB-KW.
DR   GO; GO:0050482; P:arachidonic acid secretion; IEA:InterPro.
DR   GO; GO:0016042; P:lipid catabolic process; IEA:UniProtKB-KW.
DR   GO; GO:0006644; P:phospholipid metabolic process; IEA:InterPro.
DR   InterPro; IPR036444; PLipase_A2_dom_sf.
DR   SUPFAM; SSF48619; Phospholipase A2, PLA2; 1.
PE   1: Evidence at protein level;
KW   Calcium; Calcium-activated potassium channel impairing toxin;
KW   Direct protein sequencing; Disulfide bond; Hydrolase;
KW   Ion channel impairing toxin; Lipid degradation; Lipid metabolism;
KW   Metal-binding; Neurotoxin; Potassium channel impairing toxin; Secreted;
KW   Toxin.
FT   CHAIN           <1..>27
FT                   /note="Phospholipase A2 taicatoxin"
FT                   /id="PRO_0000408515"
FT   NON_TER         1
FT   NON_TER         27
SQ   SEQUENCE   27 AA;  2901 MW;  A74F18ACB843133C CRC64;
     NLAQFGFMIR CANGGSRSAL DYADYGC
//