ID   TX35A_PHOKE             Reviewed;          50 AA.
AC   P83905;
DT   19-JUL-2004, integrated into UniProtKB/Swiss-Prot.
DT   10-MAY-2004, sequence version 1.
DT   25-MAY-2022, entry version 38.
DE   RecName: Full=U2-ctenitoxin-Pk1a {ECO:0000305};
DE            Short=U2-CNTX-Pk1a {ECO:0000305};
DE   AltName: Full=Neurotoxin PKTx20C2;
OS   Phoneutria keyserlingi (Brazilian wandering spider) (Ctenus keyserlingii).
OC   Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Chelicerata; Arachnida; Araneae;
OC   Araneomorphae; Entelegynae; Lycosoidea; Ctenidae; Phoneutria.
OX   NCBI_TaxID=272754;
RN   [1]
RP   PROTEIN SEQUENCE, SUBCELLULAR LOCATION, AND MASS SPECTROMETRY.
RC   TISSUE=Venom;
RX   PubMed=16278100; DOI=10.1016/j.cbpc.2005.09.010;
RA   Richardson M., Pimenta A.M., Bemquerer M.P., Santoro M.M., Beirao P.S.,
RA   Lima M.E., Figueiredo S.G., Bloch C. Jr., Vasconcelos E.A., Campos F.A.,
RA   Gomes P.C., Cordeiro M.N.;
RT   "Comparison of the partial proteomes of the venoms of Brazilian spiders of
RT   the genus Phoneutria.";
RL   Comp. Biochem. Physiol. 142:173-187(2006).
CC   -!- FUNCTION: Insecticidal neurotoxin that reversibly inhibits the N-
CC       methyl-D-aspartate (NMDA)-subtype of ionotropic glutamate receptor
CC       (GRIN) and inhibits inactivation of insect sodium channels (Nav). In
CC       vivo, is highly toxic to insects. {ECO:0000250|UniProtKB:P59367}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:16278100}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC       {ECO:0000305|PubMed:16278100}.
CC   -!- DOMAIN: The presence of a 'disulfide through disulfide knot'
CC       structurally defines this protein as a knottin. {ECO:0000305}.
CC   -!- MASS SPECTROMETRY: Mass=5493; Method=Electrospray;
CC       Evidence={ECO:0000269|PubMed:16278100};
CC   -!- SIMILARITY: Belongs to the neurotoxin 03 (Tx2) family. 05 subfamily.
CC       {ECO:0000305}.
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DR   AlphaFoldDB; P83905; -.
DR   ArachnoServer; AS000230; U2-ctenitoxin-Pk1a.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0035792; C:host cell postsynaptic membrane; IEA:UniProtKB-KW.
DR   GO; GO:0017080; F:sodium channel regulator activity; IEA:UniProtKB-KW.
DR   GO; GO:0090729; F:toxin activity; IEA:UniProtKB-KW.
DR   InterPro; IPR035285; CNTX.
DR   Pfam; PF17492; D_CNTX; 1.
PE   1: Evidence at protein level;
KW   Direct protein sequencing; Disulfide bond; Ion channel impairing toxin;
KW   Ionotropic glutamate receptor inhibitor; Knottin; Neurotoxin;
KW   Postsynaptic neurotoxin; Secreted; Toxin;
KW   Voltage-gated sodium channel impairing toxin.
FT   CHAIN           1..50
FT                   /note="U2-ctenitoxin-Pk1a"
FT                   /evidence="ECO:0000269|PubMed:16278100"
FT                   /id="PRO_0000087626"
FT   DISULFID        1..15
FT                   /evidence="ECO:0000305"
FT   DISULFID        8..21
FT                   /evidence="ECO:0000305"
FT   DISULFID        12..47
FT                   /evidence="ECO:0000305"
FT   DISULFID        14..31
FT                   /evidence="ECO:0000305"
FT   DISULFID        23..29
FT                   /evidence="ECO:0000305"
SQ   SEQUENCE   50 AA;  5584 MW;  FA7454A9033A98A4 CRC64;
     CGDINAPCQS DCDCCGYSVT CDCYWSKDCK CRESNFVIGM ALRKAFCKNK