ID   SCA3_MESMA              Reviewed;          85 AA.
AC   Q9GUA7;
DT   19-SEP-2003, integrated into UniProtKB/Swiss-Prot.
DT   01-MAR-2001, sequence version 1.
DT   03-AUG-2022, entry version 75.
DE   RecName: Full=Toxin BmKa3;
DE   AltName: Full=Alpha-toxin 3;
DE   AltName: Full=BmKalpha3;
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;
RA   Li W.-X., Zeng X.-C., Zhu S.-Y.;
RT   "A new cDNA sequence encoding a toxin from Buthus martensii Karsch.";
RL   Submitted (MAY-1999) to the EMBL/GenBank/DDBJ databases.
RN   [2]
RP   REVIEW.
RX   PubMed=12220709; DOI=10.1016/s0041-0101(02)00142-3;
RA   Goudet C., Chi C.-W., Tytgat J.;
RT   "An overview of toxins and genes from the venom of the Asian scorpion
RT   Buthus martensi Karsch.";
RL   Toxicon 40:1239-1258(2002).
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. {ECO:0000250}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000250}.
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; AF150009; AAG09657.1; -; mRNA.
DR   AlphaFoldDB; Q9GUA7; -.
DR   SMR; Q9GUA7; -.
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..85
FT                   /note="Toxin BmKa3"
FT                   /id="PRO_0000035256"
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   85 AA;  9426 MW;  6EFC463E02E95091 CRC64;
     MNYLVFFSLA LLLMTGVESV RDGYIADDKN CAYFCGRNAY CDDECKKKGA ESGYCQWAGV
     YGNACWCYKL PDKVPIRVPG KCNGG