ID   SCX3_TITBA              Reviewed;          62 AA.
AC   P56608;
DT   15-DEC-1998, integrated into UniProtKB/Swiss-Prot.
DT   15-DEC-1998, sequence version 1.
DT   03-AUG-2022, entry version 79.
DE   RecName: Full=Toxin Tb3;
DE   AltName: Full=P-Mice-alpha* NaTx3.3;
DE   AltName: Full=TbTx IV-5;
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, SUBCELLULAR LOCATION, AND BIOASSAY.
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: 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). Is lethal to
CC       mice (PubMed:8611151). {ECO:0000250, ECO:0000269|PubMed:8611151}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:8611151}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC       {ECO:0000305|PubMed:8611151}.
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   PIR; S62863; S62863.
DR   AlphaFoldDB; P56608; -.
DR   SMR; P56608; -.
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   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 Tb3"
FT                   /evidence="ECO:0000269|PubMed:8611151"
FT                   /id="PRO_0000066793"
FT   DOMAIN          2..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        12..62
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
FT   DISULFID        16..38
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
FT   DISULFID        24..45
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
FT   DISULFID        28..47
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
SQ   SEQUENCE   62 AA;  6978 MW;  FF8DD450F6A74CD8 CRC64;
     KKDGYPVEAD NCAFVCFGYD NAYCDKLCGD KKADSGYCYW VHILCYCYGL PDNEPTKTNG
     KC