ID   SCX2_TITBA              Reviewed;          62 AA.
AC   P56609;
DT   15-DEC-1998, integrated into UniProtKB/Swiss-Prot.
DT   15-DEC-1998, sequence version 1.
DT   03-AUG-2022, entry version 78.
DE   RecName: Full=Toxin Tb2;
DE   AltName: Full=P-beta* NaTx5.3;
DE   AltName: Full=Toxin III-8;
OS   Tityus bahiensis (Brazilian scorpion).
OC   Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Chelicerata; Arachnida;
OC   Scorpiones; Buthida; Buthoidea; Buthidae; Tityus.
OX   NCBI_TaxID=50343;
RN   [1]
RP   PROTEIN SEQUENCE.
RC   TISSUE=Venom;
RX   PubMed=8611151; DOI=10.1042/bj3130753;
RA   Becerril B., Corona M., Coronas F.I., Zamudio F.Z., Calderon-Aranda E.S.,
RA   Fletcher P.L. Jr., Martin B.M., Possani L.D.;
RT   "Toxic peptides and genes encoding toxin gamma of the Brazilian scorpions
RT   Tityus bahiensis and Tityus stigmurus.";
RL   Biochem. J. 313:753-760(1996).
RN   [2]
RP   NOMENCLATURE.
RX   PubMed=22355312; DOI=10.1371/journal.pone.0030478;
RA   Guerrero-Vargas J.A., Mourao C.B., Quintero-Hernandez V., Possani L.D.,
RA   Schwartz E.F.;
RT   "Identification and phylogenetic analysis of Tityus pachyurus and Tityus
RT   obscurus novel putative Na+-channel scorpion toxins.";
RL   PLoS ONE 7:E30478-E30478(2012).
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. This toxin is active on mammals (By
CC       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. Beta subfamily. {ECO:0000305}.
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DR   PIR; S62862; S62862.
DR   AlphaFoldDB; P56609; -.
DR   SMR; P56609; -.
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; 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   1: Evidence at protein level;
KW   Amidation; Direct protein sequencing; Disulfide bond;
KW   Ion channel impairing toxin; Neurotoxin; Secreted; Toxin;
KW   Voltage-gated sodium channel impairing toxin.
FT   CHAIN           1..62
FT                   /note="Toxin Tb2"
FT                   /id="PRO_0000066794"
FT   DOMAIN          1..62
FT                   /note="LCN-type CS-alpha/beta"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
FT   MOD_RES         62
FT                   /note="Cysteine amide"
FT                   /evidence="ECO:0000250|UniProtKB:P56611"
FT   DISULFID        11..62
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
FT   DISULFID        15..38
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
FT   DISULFID        23..43
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
FT   DISULFID        27..45
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
SQ   SEQUENCE   62 AA;  6931 MW;  69A649138CBA1CDF CRC64;
     KEGYAMDHEG CKFSCFPRPA GFCDGYCKTH LKASSGYCAW PACYCYGVPS NIKVWDYATN
     KC