ID   TX3_LOXIN               Reviewed;          86 AA.
AC   Q6B4T3;
DT   28-NOV-2006, integrated into UniProtKB/Swiss-Prot.
DT   13-SEP-2004, sequence version 1.
DT   25-MAY-2022, entry version 39.
DE   RecName: Full=U2-sicaritoxin-Li1a;
DE            Short=U2-SCRTX-Li1a;
DE   AltName: Full=LiTx3;
DE   AltName: Full=Toxin 3;
DE   Flags: Precursor;
OS   Loxosceles intermedia (Brown spider).
OC   Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Chelicerata; Arachnida; Araneae;
OC   Araneomorphae; Haplogynae; Scytodoidea; Sicariidae; Loxosceles.
OX   NCBI_TaxID=58218;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA], AND PROTEIN SEQUENCE OF 34-50.
RC   TISSUE=Venom, and Venom gland;
RX   PubMed=15302533; DOI=10.1016/j.toxicon.2004.05.028;
RA   de Castro C.S., Silvestre F.G., Araujo S.C., Yazbeck G.M., Mangili O.C.,
RA   Cruz I., Chavez-Olortegui C., Kalapothakis E.;
RT   "Identification and molecular cloning of insecticidal toxins from the venom
RT   of the brown spider Loxosceles intermedia.";
RL   Toxicon 44:273-280(2004).
CC   -!- FUNCTION: Toxin active against S.frugiperda larvae. May act on sodium
CC       channels (Nav).
CC   -!- SUBCELLULAR LOCATION: Secreted.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC   -!- DOMAIN: The presence of a 'disulfide through disulfide knot'
CC       structurally defines this protein as a knottin. {ECO:0000250}.
CC   -!- SIMILARITY: Belongs to the neurotoxin 39 family. {ECO:0000305}.
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DR   EMBL; AY681977; AAT85612.1; -; mRNA.
DR   AlphaFoldDB; Q6B4T3; -.
DR   ArachnoServer; AS000273; U2-sicaritoxin-Li1a.
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.
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..20
FT                   /evidence="ECO:0000255"
FT   PROPEP          21..33
FT                   /evidence="ECO:0000269|PubMed:15302533"
FT                   /id="PRO_0000262661"
FT   CHAIN           34..86
FT                   /note="U2-sicaritoxin-Li1a"
FT                   /id="PRO_0000262662"
FT   DISULFID        35..53
FT                   /evidence="ECO:0000250"
FT   DISULFID        42..62
FT                   /evidence="ECO:0000250"
FT   DISULFID        52..71
FT                   /evidence="ECO:0000250"
FT   DISULFID        64..69
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   86 AA;  9319 MW;  8B2BBF839020DEBD CRC64;
     MTFKLFVVVT LVLAIYVATA EEAMKDDSEP AERGCIKYGD RCGSPHGLPS NCCNDWKYKG
     RCGCTMGVCT CGPNCPSRGC DWSKKG