ID   BEST_PARTR              Reviewed;          58 AA.
AC   P0C1B6;
DT   02-MAY-2006, integrated into UniProtKB/Swiss-Prot.
DT   02-MAY-2006, sequence version 1.
DT   25-MAY-2022, entry version 46.
DE   RecName: Full=Bestoxin;
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, AND MASS SPECTROMETRY.
RC   TISSUE=Venom;
RX   PubMed=15804521; DOI=10.1016/j.toxicon.2005.01.020;
RA   Inceoglu A.B., Lango J., Pessah I.N., Hammock B.D.;
RT   "Three structurally related, highly potent, peptides from the venom of
RT   Parabuthus transvaalicus possess divergent biological activity.";
RL   Toxicon 45:727-733(2005).
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 (By similarity). In mice, causes
CC       intense writhing. {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   -!- MASS SPECTROMETRY: Mass=6603.6; Method=Electrospray;
CC       Evidence={ECO:0000269|PubMed:15804521};
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; P0C1B6; -.
DR   SMR; P0C1B6; -.
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="Bestoxin"
FT                   /id="PRO_0000233629"
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;  6607 MW;  A5FD4ED9FC7794C2 CRC64;
     ADVPGNYPLD KDGNTYTCLE LGENKDCQKV CKLHGVQYGY CYAFSCWCKE YLDDKDSV