ID   KA124_TITST             Reviewed;          40 AA.
AC   P0C8L1;
DT   16-DEC-2008, integrated into UniProtKB/Swiss-Prot.
DT   16-DEC-2008, sequence version 1.
DT   25-MAY-2022, entry version 34.
DE   RecName: Full=Potassium channel toxin alpha-KTx 12.4;
DE   AltName: Full=Butantoxin;
DE            Short=BuTX;
DE            Short=TstBut;
OS   Tityus stigmurus (Brazilian scorpion).
OC   Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Chelicerata; Arachnida;
OC   Scorpiones; Buthida; Buthoidea; Buthidae; Tityus.
OX   NCBI_TaxID=50344;
RN   [1]
RP   PROTEIN SEQUENCE, STRUCTURE BY NMR, AND DISULFIDE BONDS.
RC   TISSUE=Venom;
RX   PubMed=10864437; DOI=10.1006/abbi.2000.1858;
RA   Holaday S.K. Jr., Martin B.M., Fletcher P.L. Jr., Krishna N.R.;
RT   "NMR solution structure of butantoxin.";
RL   Arch. Biochem. Biophys. 379:18-27(2000).
RN   [2]
RP   PROTEIN SEQUENCE, AND MASS SPECTROMETRY.
RC   TISSUE=Venom;
RX   PubMed=17270501; DOI=10.1016/j.cbpc.2006.12.004;
RA   Batista C.V.F., Roman-Gonzalez S.A., Salas-Castillo S.P., Zamudio F.Z.,
RA   Gomez-Lagunas F., Possani L.D.;
RT   "Proteomic analysis of the venom from the scorpion Tityus stigmurus:
RT   biochemical and physiological comparison with other Tityus species.";
RL   Comp. Biochem. Physiol. 146C:147-157(2007).
CC   -!- FUNCTION: Inhibits high conductance calcium-activated potassium
CC       channels. Reversibly inhibits Shaker B potassium channels (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   -!- MASS SPECTROMETRY: Mass=4506.6; Method=Electrospray;
CC       Evidence={ECO:0000269|PubMed:17270501};
CC   -!- SIMILARITY: Belongs to the short scorpion toxin superfamily. Potassium
CC       channel inhibitor family. Alpha-KTx 12 subfamily. {ECO:0000305}.
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DR   AlphaFoldDB; P0C8L1; -.
DR   BMRB; P0C8L1; -.
DR   SMR; P0C8L1; -.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0008200; F:ion channel inhibitor activity; IEA:InterPro.
DR   GO; GO:0015459; F:potassium channel regulator activity; IEA:UniProtKB-KW.
DR   GO; GO:0090729; F:toxin activity; IEA:UniProtKB-KW.
DR   Gene3D; 3.30.30.10; -; 1.
DR   InterPro; IPR036574; Scorpion_toxin-like_sf.
DR   InterPro; IPR001947; Scorpion_toxinS_K_inh.
DR   Pfam; PF00451; Toxin_2; 1.
DR   PRINTS; PR00286; CHARYBDTOXIN.
DR   SUPFAM; SSF57095; SSF57095; 1.
DR   PROSITE; PS01138; SCORP_SHORT_TOXIN; 1.
PE   1: Evidence at protein level;
KW   Calcium-activated potassium channel impairing toxin;
KW   Direct protein sequencing; Disulfide bond; Ion channel impairing toxin;
KW   Neurotoxin; Potassium channel impairing toxin; Secreted; Toxin.
FT   CHAIN           1..40
FT                   /note="Potassium channel toxin alpha-KTx 12.4"
FT                   /id="PRO_0000356889"
FT   SITE            30
FT                   /note="Basic residue of the functional dyad"
FT                   /evidence="ECO:0000250"
FT   SITE            39
FT                   /note="Aromatic residue of the functional dyad"
FT                   /evidence="ECO:0000250"
FT   DISULFID        2..5
FT                   /evidence="ECO:0000269|PubMed:10864437"
FT   DISULFID        10..31
FT                   /evidence="ECO:0000269|PubMed:10864437"
FT   DISULFID        16..36
FT                   /evidence="ECO:0000269|PubMed:10864437"
FT   DISULFID        20..38
FT                   /evidence="ECO:0000269|PubMed:10864437"
SQ   SEQUENCE   40 AA;  4514 MW;  79C47786312FC1BD CRC64;
     WCSTCLDLAC GASRECYDPC FKAFGRAHGK CMNNKCRCYT