ID   TX34A_PHONI             Reviewed;          88 AA.
AC   P29423;
DT   01-APR-1993, integrated into UniProtKB/Swiss-Prot.
DT   15-JUL-1999, sequence version 2.
DT   25-MAY-2022, entry version 70.
DE   RecName: Full=U2-ctenitoxin-Pn1a;
DE            Short=U2-CNTX-Pn1a;
DE   AltName: Full=Neurotoxin Tx2-1;
DE   Flags: Precursor;
OS   Phoneutria nigriventer (Brazilian armed spider) (Ctenus nigriventer).
OC   Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Chelicerata; Arachnida; Araneae;
OC   Araneomorphae; Entelegynae; Lycosoidea; Ctenidae; Phoneutria.
OX   NCBI_TaxID=6918;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA].
RC   TISSUE=Venom gland;
RX   PubMed=9839668; DOI=10.1016/s0041-0101(98)00105-6;
RA   Kalapothakis E., Penaforte C.L., Beirao P.S.L., Romano-Silva M.A.,
RA   Cruz J.S., Prado M.A.M., Guimaraes P.E.M., Gomez M.V., Prado V.F.;
RT   "Cloning of cDNAS encoding neurotoxic peptides from the spider Phoneutria
RT   nigriventer.";
RL   Toxicon 36:1843-1850(1998).
RN   [2]
RP   PROTEIN SEQUENCE OF 35-87.
RC   TISSUE=Venom;
RX   PubMed=1397265; DOI=10.1016/0014-5793(92)81318-g;
RA   Cordeiro M.N., Diniz C.R., Valentim A.D.C., von Eickstedt V.R.D.,
RA   Gilroy J., Richardson M.;
RT   "The purification and amino acid sequences of four Tx2 neurotoxins from the
RT   venom of the Brazilian 'armed' spider Phoneutria nigriventer (Keys).";
RL   FEBS Lett. 310:153-156(1992).
RN   [3]
RP   PROTEIN SEQUENCE OF 35-87, SUBCELLULAR LOCATION, TISSUE SPECIFICITY, AND
RP   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: Inhibits voltage-gated sodium channels (Nav) (By similarity).
CC       Causes scratching, lacrimation, hypersalivation, sweating and agitation
CC       followed by spastic paralysis of the anterior and posterior extremities
CC       and death at dose levels of 1.62 mg/mouse. Insecticidal to the larval
CC       and adult forms of the house fly. {ECO:0000250}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:16278100}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC       {ECO:0000269|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=5838.8; Method=Unknown;
CC       Evidence={ECO:0000269|PubMed:16278100};
CC   -!- SIMILARITY: Belongs to the neurotoxin 03 (Tx2) family. 04 subfamily.
CC       {ECO:0000305}.
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DR   EMBL; AF014464; AAC26166.1; -; mRNA.
DR   PIR; S29214; S29214.
DR   AlphaFoldDB; P29423; -.
DR   ArachnoServer; AS000234; U2-ctenitoxin-Pn1a.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
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   Knottin; Neurotoxin; Secreted; Signal; Toxin;
KW   Voltage-gated sodium channel impairing toxin.
FT   SIGNAL          1..17
FT                   /evidence="ECO:0000255"
FT   PROPEP          18..34
FT                   /id="PRO_0000035495"
FT   CHAIN           35..87
FT                   /note="U2-ctenitoxin-Pn1a"
FT                   /id="PRO_0000035496"
FT   PROPEP          88
FT                   /id="PRO_0000035497"
FT   DISULFID        37..51
FT                   /evidence="ECO:0000305"
FT   DISULFID        44..57
FT                   /evidence="ECO:0000305"
FT   DISULFID        48..86
FT                   /evidence="ECO:0000305"
FT   DISULFID        50..71
FT                   /evidence="ECO:0000305"
FT   DISULFID        59..69
FT                   /evidence="ECO:0000305"
SQ   SEQUENCE   88 AA;  9841 MW;  D8AD07C6A769E647 CRC64;
     MKVAILILSI LVLAVASETI EEYRDDFAVE ELERATCAGQ DKPCKETCDC CGERGECVCA
     LSYEGKYRCI CRQGNFLIAW HKLASCKK