ID   STX3_ENTQU              Reviewed;          32 AA.
AC   P09949;
DT   01-JUL-1989, integrated into UniProtKB/Swiss-Prot.
DT   16-SEP-2015, sequence version 2.
DT   25-MAY-2022, entry version 72.
DE   RecName: Full=Delta-actitoxin-Eqd1a {ECO:0000303|PubMed:22683676};
DE            Short=Delta-AITX-Eqd1a {ECO:0000303|PubMed:22683676};
DE   AltName: Full=Delta-actitoxin-Ers1a {ECO:0000303|PubMed:22683676};
DE            Short=Delta-AITX-Ers1a {ECO:0000303|PubMed:22683676};
DE   AltName: Full=Er-I {ECO:0000303|PubMed:22683676};
DE            Short=Er I {ECO:0000303|PubMed:12676443};
DE   AltName: Full=Neurotoxin 3 homolog {ECO:0000305|PubMed:2862037};
DE   AltName: Full=Neurotoxin III homolog {ECO:0000305|PubMed:2862037};
DE   AltName: Full=Parasicyonis toxin {ECO:0000303|PubMed:6107210};
DE            Short=PATX {ECO:0000303|PubMed:6107210};
OS   Entacmaea quadricolor (Bubble-tip anemone) (Parasicyonis actinostoloides).
OC   Eukaryota; Metazoa; Cnidaria; Anthozoa; Hexacorallia; Actiniaria;
OC   Actiniidae; Entacmaea.
OX   NCBI_TaxID=6118;
RN   [1]
RP   PROTEIN SEQUENCE OF 1-31.
RX   PubMed=12676443; DOI=10.1016/s0041-0101(02)00368-9;
RA   Honma T., Iso T., Ishida M., Nagashima Y., Shiomi K.;
RT   "Occurrence of type 3 sodium channel peptide toxins in two species of sea
RT   anemones (Dofleinia armata and Entacmaea ramsayi).";
RL   Toxicon 41:637-639(2003).
RN   [2]
RP   PROTEIN SEQUENCE.
RC   TISSUE=Nematoblast;
RX   PubMed=2862037; DOI=10.1111/j.1432-1033.1985.tb09003.x;
RA   Nishida S., Fujita S., Warashina A., Satake M., Tamiya N.;
RT   "Amino acid sequence of a sea anemone toxin from Parasicyonis
RT   actinostoloides.";
RL   Eur. J. Biochem. 150:171-173(1985).
RN   [3]
RP   FUNCTION, AND TOXIC DOSE.
RX   PubMed=37290; DOI=10.1111/j.1471-4159.1979.tb11707.x;
RA   Ishikawa Y., Onodera K., Takeuchi A.;
RT   "Purification and effect of the neurotoxin from the sea anemone
RT   Parasicyonis actinostoloides.";
RL   J. Neurochem. 33:69-73(1979).
RN   [4]
RP   FUNCTION.
RX   PubMed=6107210; DOI=10.1016/0306-4492(80)90060-x;
RA   Fujita S., Warashina A.;
RT   "Parasicyonis toxin: effect on crayfish giant axon.";
RL   Comp. Biochem. Physiol. 67C:71-74(1980).
RN   [5]
RP   NOMENCLATURE.
RX   PubMed=22683676; DOI=10.1016/j.toxicon.2012.05.020;
RA   Oliveira J.S., Fuentes-Silva D., King G.F.;
RT   "Development of a rational nomenclature for naming peptide and protein
RT   toxins from sea anemones.";
RL   Toxicon 60:539-550(2012).
CC   -!- FUNCTION: Binds specifically to sodium channels (Nav) of the axonal
CC       membrane of crayfish and prolongs the falling phase of the action
CC       potential. It also increases the maximum rates of rise of both action
CC       potential and resting potential (PubMed:6107210). Is only active on
CC       crustaceans. {ECO:0000269|PubMed:37290, ECO:0000269|PubMed:6107210}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000305}. Nematocyst {ECO:0000305}.
CC   -!- PTM: Contains 4 disulfide bonds.
CC   -!- TOXIC DOSE: LD(50) is 10 pg/kg when injected into crabs.
CC       {ECO:0000269|PubMed:37290}.
CC   -!- SIMILARITY: Belongs to the sea anemone short toxin (type III) family.
CC       {ECO:0000305}.
CC   -!- CAUTION: PubMed:12676443 describes this protein as coming from
CC       E.ramsayi, which is considered in this reference as a synonym of
CC       E.quadricolor. {ECO:0000305|PubMed:12676443}.
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   PIR; A25210; A25210.
DR   AlphaFoldDB; P09949; -.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0042151; C:nematocyst; IEA:UniProtKB-SubCell.
DR   GO; GO:0019871; F:sodium channel inhibitor activity; IEA:InterPro.
DR   GO; GO:0090729; F:toxin activity; IEA:UniProtKB-KW.
DR   InterPro; IPR016330; Neurotoxin_3_Actiniidae.
DR   InterPro; IPR012509; Neurotoxin_3_Anemonia.
DR   Pfam; PF08098; ATX_III; 1.
DR   PIRSF; PIRSF001906; Neurotoxin_III_Actiniidae; 1.
PE   1: Evidence at protein level;
KW   Direct protein sequencing; Disulfide bond; Ion channel impairing toxin;
KW   Nematocyst; Neurotoxin; Secreted; Toxin;
KW   Voltage-gated sodium channel impairing toxin.
FT   PEPTIDE         1..32
FT                   /note="Delta-actitoxin-Eqd1a"
FT                   /evidence="ECO:0000269|PubMed:2862037"
FT                   /id="PRO_0000044861"
SQ   SEQUENCE   32 AA;  3252 MW;  4259CBEE4131B68A CRC64;
     AGGKSTCCPC AMCKYTAGCP WGQCAHHCGC SE