PA2T_OXYSC
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 25-MAY-2022, entry version 68.
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; SSF48619; 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
