ID   SC13_MESMA              Reviewed;          84 AA.
AC   Q9NJC8;
DT   19-DEC-2001, integrated into UniProtKB/Swiss-Prot.
DT   01-OCT-2000, sequence version 1.
DT   03-AUG-2022, entry version 77.
DE   RecName: Full=Toxin BmKaTx13;
DE   AltName: Full=Alpha-neurotoxin Tx13;
DE   AltName: Full=BmKalphaTx13;
DE   Flags: Precursor;
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;
RX   PubMed=10858508; DOI=10.1016/s0041-0101(00)00081-7;
RA   Zhu S.-Y., Li W.-X., Zeng X.-C., Liu H., Jiang D.-H., Mao X.;
RT   "Nine novel precursors of Buthus martensii scorpion alpha-toxin
RT   homologues.";
RL   Toxicon 38:1653-1661(2000).
CC   -!- FUNCTION: Alpha toxins bind voltage-independently at site-3 of sodium
CC       channels (Nav) and inhibit the inactivation of the activated channels,
CC       thereby blocking neuronal transmission. This toxin is active against
CC       mammals (By 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. Alpha subfamily. {ECO:0000305}.
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DR   EMBL; AF155363; AAF31477.1; -; mRNA.
DR   PIR; JE0143; JE0143.
DR   AlphaFoldDB; Q9NJC8; -.
DR   SMR; Q9NJC8; -.
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   Disulfide bond; Ion channel impairing toxin; Neurotoxin; Secreted; Signal;
KW   Toxin; Voltage-gated sodium channel impairing toxin.
FT   SIGNAL          1..19
FT                   /evidence="ECO:0000250"
FT   CHAIN           20..83
FT                   /note="Toxin BmKaTx13"
FT                   /id="PRO_0000035248"
FT   PROPEP          84
FT                   /note="Removed by a carboxypeptidase"
FT                   /evidence="ECO:0000305"
FT                   /id="PRO_0000035249"
FT   DOMAIN          21..83
FT                   /note="LCN-type CS-alpha/beta"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
FT   DISULFID        31..82
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
FT   DISULFID        35..55
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
FT   DISULFID        41..65
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
FT   DISULFID        45..67
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
SQ   SEQUENCE   84 AA;  9319 MW;  467FFD159A223530 CRC64;
     MNYLVMISFA LLLMKGVESV RDAYIAKPEN CVYHCAGNEG CNKLCTDNGA ESGYCQWGGR
     YGNACWCIKL PDDVPIRVPG KCHR