ID   BIRT_PARTR              Reviewed;          58 AA.
AC   P58752;
DT   27-MAR-2002, integrated into UniProtKB/Swiss-Prot.
DT   27-MAR-2002, sequence version 1.
DT   25-MAY-2022, entry version 67.
DE   RecName: Full=Birtoxin;
OS   Parabuthus transvaalicus (South African fattail scorpion).
OC   Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Chelicerata; Arachnida;
OC   Scorpiones; Buthida; Buthoidea; Buthidae; Parabuthus.
OX   NCBI_TaxID=170972;
RN   [1]
RP   PROTEIN SEQUENCE.
RC   TISSUE=Venom;
RX   PubMed=11606203; DOI=10.1046/j.0014-2956.2001.02479.x;
RA   Inceoglu A.B., Lango J., Wu J., Hawkins P., Southern J., Hammock B.D.;
RT   "Isolation and characterization of a novel type of neurotoxic peptide from
RT   the venom of the South African scorpion Parabuthus transvaalicus
RT   (Buthidae).";
RL   Eur. J. Biochem. 268:5407-5413(2001).
RN   [2]
RP   FUNCTION, AND MASS SPECTROMETRY.
RX   PubMed=12423335; DOI=10.1046/j.1432-1033.2002.03171.x;
RA   Inceoglu A.B., Hayashida Y., Lango J., Ishida A.T., Hammock B.D.;
RT   "A single charged surface residue modifies the activity of ikitoxin, a
RT   beta-type Na+ channel toxin from Parabuthus transvaalicus.";
RL   Eur. J. Biochem. 269:5369-5376(2002).
CC   -!- FUNCTION: Beta toxins bind voltage-independently at site-4 of sodium
CC       channels (Nav) and shift the voltage of activation toward more negative
CC       potentials thereby affecting sodium channel activation and promoting
CC       spontaneous and repetitive firing. Moderately toxic, but very high
CC       abundant. Does not target reptilian channels. Does not produce effect
CC       when administered to blowfly and cabbage looper larvae. In mice,
CC       produces convulsions, tremors, increased ventilation and, subsequently,
CC       death. {ECO:0000269|PubMed:12423335}.
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=6543; Method=MALDI;
CC       Evidence={ECO:0000269|PubMed:12423335};
CC   -!- SIMILARITY: Belongs to the long (3 C-C) scorpion toxin superfamily.
CC       Sodium channel inhibitor family. Beta subfamily. {ECO:0000305}.
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DR   AlphaFoldDB; P58752; -.
DR   SMR; P58752; -.
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   Gene3D; 3.30.30.10; -; 1.
DR   InterPro; IPR044062; LCN-type_CS_alpha_beta_dom.
DR   InterPro; IPR036574; Scorpion_toxin-like_sf.
DR   InterPro; IPR002061; Scorpion_toxinL/defensin.
DR   Pfam; PF00537; Toxin_3; 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..58
FT                   /note="Birtoxin"
FT                   /id="PRO_0000066791"
FT   DOMAIN          3..58
FT                   /note="LCN-type CS-alpha/beta"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
FT   DISULFID        18..41
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
FT   DISULFID        27..46
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
FT   DISULFID        31..48
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
SQ   SEQUENCE   58 AA;  6548 MW;  F5C9EA421959D096 CRC64;
     ADVPGNYPLD KDGNTYKCFL LGGNEECLNV CKLHGVQYGY CYASKCWCEY LEDDKDSV