ID   SIX3_MESMA              Reviewed;          64 AA.
AC   Q17231;
DT   07-DEC-2004, integrated into UniProtKB/Swiss-Prot.
DT   07-DEC-2004, sequence version 2.
DT   03-AUG-2022, entry version 80.
DE   RecName: Full=Toxin BmKIT3;
DE            Short=BmK IT3;
DE   AltName: Full=Insect toxin 3;
OS   Mesobuthus martensii (Manchurian scorpion) (Buthus martensii).
OC   Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Chelicerata; Arachnida;
OC   Scorpiones; Buthida; Buthoidea; Buthidae; Mesobuthus.
OX   NCBI_TaxID=34649;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA].
RC   TISSUE=Venom gland;
RA   Zhu X., Zhang T., Zhu Y.;
RT   "Cloning and sequencing of two depressant insect selective neurotoxin cDNAs
RT   from Buthus martensii Karsch.";
RL   Chin. Sci. Bull. 41:1387-1391(1996).
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 (By
CC       similarity). {ECO:0000250}.
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   -!- SIMILARITY: Belongs to the long (4 C-C) scorpion toxin superfamily.
CC       Sodium channel inhibitor family. Beta subfamily. {ECO:0000305}.
CC   -!- SEQUENCE CAUTION:
CC       Sequence=CAA63059.1; Type=Erroneous initiation; Evidence={ECO:0000305};
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DR   EMBL; X92077; CAA63059.1; ALT_INIT; mRNA.
DR   AlphaFoldDB; Q17231; -.
DR   SMR; Q17231; -.
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   2: Evidence at transcript level;
KW   Amidation; Disulfide bond; Ion channel impairing toxin; Neurotoxin;
KW   Secreted; Toxin; Voltage-gated sodium channel impairing toxin.
FT   CHAIN           1..60
FT                   /note="Toxin BmKIT3"
FT                   /id="PRO_0000035201"
FT   DOMAIN          1..61
FT                   /note="LCN-type CS-alpha/beta"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
FT   MOD_RES         60
FT                   /note="Cysteine amide"
FT                   /evidence="ECO:0000255"
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   64 AA;  7154 MW;  97A93D17C5755626 CRC64;
     DGYIRGSNGC KVSCLWGNEG CNKECRAYGA SYGYCWTWGL ACWCEGLPDD KTWKSESNTC
     GRKK