ID   SIX3_HOTTS              Reviewed;          61 AA.
AC   P82813;
DT   26-SEP-2001, integrated into UniProtKB/Swiss-Prot.
DT   26-SEP-2001, sequence version 1.
DT   03-AUG-2022, entry version 72.
DE   RecName: Full=Insect toxin BsIT3;
DE            Short=Insect toxin 3;
DE   AltName: Full=Bs-dprIT3;
OS   Hottentotta tamulus sindicus (Scorpion) (Buthus sindicus).
OC   Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Chelicerata; Arachnida;
OC   Scorpiones; Buthida; Buthoidea; Buthidae; Mesobuthus.
OX   NCBI_TaxID=42519;
RN   [1]
RP   PROTEIN SEQUENCE, FUNCTION, TOXIC DOSE, AND MASS SPECTROMETRY.
RC   TISSUE=Venom;
RX   PubMed=11437351; DOI=10.1006/abbi.2001.2363;
RA   Ali S.A., Stoeva S., Grossmann J.G., Abbasi A., Voelter W.;
RT   "Purification, characterization, and primary structure of four depressant
RT   insect-selective neurotoxin analogs from scorpion (Buthus sindicus)
RT   venom.";
RL   Arch. Biochem. Biophys. 391:197-206(2001).
CC   -!- FUNCTION: Depressant insect beta-toxins cause a transient contraction
CC       paralysis followed by a slow flaccid paralysis. They bind voltage-
CC       independently at site-4 of sodium channels (Nav) and shift the voltage
CC       of activation toward more negative potentials thereby affecting sodium
CC       channel activation and promoting spontaneous and repetitive firing.
CC       This toxin is active only on insects. {ECO:0000269|PubMed:11437351}.
CC   -!- SUBCELLULAR LOCATION: Secreted.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC   -!- DOMAIN: Has the structural arrangement of an alpha-helix connected to
CC       antiparallel beta-sheets by disulfide bonds (CS-alpha/beta).
CC       {ECO:0000305}.
CC   -!- MASS SPECTROMETRY: Mass=6714.7; Method=Electrospray;
CC       Evidence={ECO:0000269|PubMed:11437351};
CC   -!- TOXIC DOSE: LD(50) is 163 ng/100 mg of body weight of cockroach
CC       (B.germanica) and 103 ng/100 mg of body weight of blowfly larvae
CC       (S.falculata). {ECO:0000269|PubMed:11437351}.
CC   -!- SIMILARITY: Belongs to the long (4 C-C) scorpion toxin superfamily.
CC       Sodium channel inhibitor family. Beta subfamily. {ECO:0000305}.
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DR   PIR; C59352; C59352.
DR   AlphaFoldDB; P82813; -.
DR   SMR; P82813; -.
DR   GO; GO:0005576; C:extracellular region; 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   GO; GO:0006952; P:defense response; IEA:InterPro.
DR   CDD; cd00107; Knot1; 1.
DR   Gene3D; 3.30.30.10; -; 1.
DR   InterPro; IPR044062; LCN-type_CS_alpha_beta_dom.
DR   InterPro; IPR003614; Scorpion_toxin-like.
DR   InterPro; IPR036574; Scorpion_toxin-like_sf.
DR   InterPro; IPR018218; Scorpion_toxinL.
DR   InterPro; IPR002061; Scorpion_toxinL/defensin.
DR   Pfam; PF00537; Toxin_3; 1.
DR   PRINTS; PR00285; SCORPNTOXIN.
DR   SMART; SM00505; Knot1; 1.
DR   SUPFAM; SSF57095; SSF57095; 1.
DR   PROSITE; PS51863; LCN_CSAB; 1.
PE   1: Evidence at protein level;
KW   Direct protein sequencing; Disulfide bond; Ion channel impairing toxin;
KW   Neurotoxin; Secreted; Toxin; Voltage-gated sodium channel impairing toxin.
FT   CHAIN           1..61
FT                   /note="Insect toxin BsIT3"
FT                   /id="PRO_0000066720"
FT   DOMAIN          1..61
FT                   /note="LCN-type CS-alpha/beta"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
FT   DISULFID        10..60
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
FT   DISULFID        14..35
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
FT   DISULFID        21..42
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
FT   DISULFID        25..44
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
SQ   SEQUENCE   61 AA;  6715 MW;  765448D42F6655AA CRC64;
     DGYILNSKGC KVSCVVSIVY CNSMCKSSGG SYGYCWTWGL ACWCEGLPNS KRWTSSKNKC
     N