ID   SCX4_TITFA              Reviewed;          62 AA.
AC   P83435;
DT   01-NOV-2002, integrated into UniProtKB/Swiss-Prot.
DT   01-OCT-2002, sequence version 1.
DT   03-AUG-2022, entry version 67.
DE   RecName: Full=Alpha-toxin Tf4 {ECO:0000303|PubMed:12782073};
DE   AltName: Full=Neurotoxin 4;
DE   AltName: Full=P-Frog-alpha NaTx4.4;
OS   Tityus fasciolatus (Central Brazilian scorpion).
OC   Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Chelicerata; Arachnida;
OC   Scorpiones; Buthida; Buthoidea; Buthidae; Tityus.
OX   NCBI_TaxID=203543;
RN   [1]
RP   PROTEIN SEQUENCE, FUNCTION, SUBCELLULAR LOCATION, TISSUE SPECIFICITY, AND
RP   MASS SPECTROMETRY.
RC   TISSUE=Venom;
RX   PubMed=12782073; DOI=10.1016/s0041-0101(03)00008-4;
RA   Wagner S., Castro M.S., Barbosa J.A.R.G., Fontes W., Schwartz E.N.F.,
RA   Sebben A., Pires O.R. Jr., Sousa M.V., Schwartz C.A.;
RT   "Purification and primary structure determination of Tf4, the first
RT   bioactive peptide isolated from the venom of the Brazilian scorpion Tityus
RT   fasciolatus.";
RL   Toxicon 41:737-745(2003).
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 (PubMed:12782073). This toxin is
CC       toxic to frogs but non-toxic to insect larvae (T.molitor), mammals
CC       (rats) and crustaceans (crabs) at the doses assayed (PubMed:12782073).
CC       {ECO:0000269|PubMed:12782073}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:12782073,
CC       ECO:0000305}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC       {ECO:0000269|PubMed:12782073}.
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=6614.30; Method=Electrospray;
CC       Evidence={ECO:0000269|PubMed:12782073};
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   AlphaFoldDB; P83435; -.
DR   SMR; P83435; -.
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="Alpha-toxin Tf4"
FT                   /evidence="ECO:0000269|PubMed:12782073"
FT                   /id="PRO_0000066827"
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:P0DQH6"
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..43
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
FT   DISULFID        28..45
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01210"
SQ   SEQUENCE   62 AA;  6623 MW;  75754FB1429B9F24 CRC64;
     GKEGYPADSK GCKVTCFFTG VGYCDTECKL KKASSGYCAW PACYCYGLPD SASVWDSATN
     KC