ID   SCX4A_ANDCR             Reviewed;          79 AA.
AC   D5HR53;
DT   01-APR-2015, integrated into UniProtKB/Swiss-Prot.
DT   15-JUN-2010, sequence version 1.
DT   25-MAY-2022, entry version 26.
DE   RecName: Full=Anti-insect Ac4;
DE   AltName: Full=Neurotoxin 4;
DE   Flags: Precursor;
OS   Androctonus crassicauda (Arabian fat-tailed scorpion).
OC   Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Chelicerata; Arachnida;
OC   Scorpiones; Buthida; Buthoidea; Buthidae; Androctonus.
OX   NCBI_TaxID=122909;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA], AND FUNCTION.
RC   TISSUE=Venom gland;
RX   PubMed=20018978; DOI=10.1093/molbev/msp310;
RA   Weinberger H., Moran Y., Gordon D., Turkov M., Kahn R., Gurevitz M.;
RT   "Positions under positive selection--key for selectivity and potency of
RT   scorpion alpha-toxins.";
RL   Mol. Biol. Evol. 27:1025-1034(2010).
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 (By similarity). This protein is
CC       weakly toxic against insects (ED(50)>2 ug per 100 mg of blowfly
CC       larvae), but is inactive against mammalian sodium channels (rNav1.2a,
CC       and rNav1.4) (PubMed:20018978). {ECO:0000250,
CC       ECO:0000269|PubMed:20018978}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000250}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland. {ECO:0000305}.
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; GQ335453; ADE42765.1; -; mRNA.
DR   AlphaFoldDB; D5HR53; -.
DR   SMR; D5HR53; -.
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   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; IPR002061; Scorpion_toxinL/defensin.
DR   Pfam; PF00537; Toxin_3; 1.
DR   SMART; SM00505; Knot1; 1.
DR   SUPFAM; SSF57095; SSF57095; 1.
DR   PROSITE; PS51863; LCN_CSAB; 1.
PE   3: Inferred from homology;
KW   Cleavage on pair of basic residues; Disulfide bond;
KW   Ion channel impairing toxin; Neurotoxin; Secreted; Signal; Toxin;
KW   Voltage-gated sodium channel impairing toxin.
FT   SIGNAL          1..17
FT                   /evidence="ECO:0000255"
FT   CHAIN           18..77
FT                   /note="Anti-insect Ac4"
FT                   /id="PRO_5000585061"
FT   DOMAIN          18..77
FT                   /note="LCN-type CS-alpha/beta"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
FT   DISULFID        26..76
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
FT   DISULFID        30..48
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
FT   DISULFID        34..58
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
FT   DISULFID        38..60
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
SQ   SEQUENCE   79 AA;  8516 MW;  243C1A6CB450739A CRC64;
     MISLSLLLMI GVESVRDGYI VDFKNCVYRC VPPCDGLCKK NGGKGGSCSF LIGSGLACWC
     NALPDNVPIK DPLHKCPKR