ID   KA182_TITDI             Reviewed;          34 AA.
AC   P0C1X5;
DT   19-SEP-2006, integrated into UniProtKB/Swiss-Prot.
DT   19-SEP-2006, sequence version 1.
DT   25-MAY-2022, entry version 36.
DE   RecName: Full=Potassium channel toxin alpha-KTx 18.2;
DE   AltName: Full=Toxin TdK2 {ECO:0000303|PubMed:16705749};
OS   Tityus discrepans (Venezuelan scorpion).
OC   Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Chelicerata; Arachnida;
OC   Scorpiones; Buthida; Buthoidea; Buthidae; Tityus.
OX   NCBI_TaxID=57059;
RN   [1]
RP   PROTEIN SEQUENCE, MASS SPECTROMETRY, SUBCELLULAR LOCATION, AND FUNCTION.
RC   TISSUE=Venom;
RX   PubMed=16705749; DOI=10.1002/pmic.200500525;
RA   Batista C.V.F., D'Suze G., Gomez-Lagunas F., Zamudio F.Z., Encarnacion S.,
RA   Sevcik C., Possani L.D.;
RT   "Proteomic analysis of Tityus discrepans scorpion venom and amino acid
RT   sequence of novel toxins.";
RL   Proteomics 6:3718-3727(2006).
RN   [2]
RP   3D-STRUCTURE MODELING.
RX   PubMed=22332965; DOI=10.1021/bi201713z;
RA   Stehling E.G., Sforca M.L., Zanchin N.I., Oyama S. Jr., Pignatelli A.,
RA   Belluzzi O., Polverini E., Corsini R., Spisni A., Pertinhez T.A.;
RT   "Looking over toxin-K(+) channel interactions. Clues from the structural
RT   and functional characterization of alpha-KTx toxin Tc32, a Kv1.3 channel
RT   blocker.";
RL   Biochemistry 51:1885-1894(2012).
CC   -!- FUNCTION: Reversibly blocks Shaker B potassium channels.
CC       {ECO:0000269|PubMed:16705749}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:16705749}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland. {ECO:0000305}.
CC   -!- DOMAIN: Has the structural arrangement of an alpha-helix connected to a
CC       beta-sheet by disulfide bonds (CSalpha/beta).
CC       {ECO:0000250|UniProtKB:P60211}.
CC   -!- MASS SPECTROMETRY: Mass=3451.4; Method=Electrospray;
CC       Evidence={ECO:0000269|PubMed:16705749};
CC   -!- SIMILARITY: Belongs to the short scorpion toxin superfamily. Potassium
CC       channel inhibitor family. Alpha-KTx 18 subfamily. {ECO:0000305}.
CC   -!- CAUTION: Lacks the dyad motif characteristic of alpha-KTx and generally
CC       associated with channel blockage. {ECO:0000305}.
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DR   AlphaFoldDB; P0C1X5; -.
DR   SMR; P0C1X5; -.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0015459; F:potassium channel regulator activity; IEA:UniProtKB-KW.
DR   GO; GO:0090729; F:toxin activity; IEA:UniProtKB-KW.
PE   1: Evidence at protein level;
KW   Direct protein sequencing; Disulfide bond; Ion channel impairing toxin;
KW   Neurotoxin; Potassium channel impairing toxin; Secreted; Toxin;
KW   Voltage-gated potassium channel impairing toxin.
FT   PEPTIDE         1..34
FT                   /note="Potassium channel toxin alpha-KTx 18.2"
FT                   /evidence="ECO:0000269|PubMed:16705749"
FT                   /id="PRO_0000249964"
FT   SITE            17
FT                   /note="Penetrates into Kv1.1 and Kv1.3 pores (when K-21
FT                   does not penetrate into it)"
FT                   /evidence="ECO:0000305|PubMed:22332965"
FT   SITE            21
FT                   /note="Penetrates into Kv1.1 and Kv1.3 pores (when K-17
FT                   does not penetrate into it)"
FT                   /evidence="ECO:0000305|PubMed:22332965"
FT   DISULFID        7..26
FT                   /evidence="ECO:0000250|UniProtKB:P60211"
FT   DISULFID        12..31
FT                   /evidence="ECO:0000250|UniProtKB:P60211"
FT   DISULFID        16..33
FT                   /evidence="ECO:0000250|UniProtKB:P60211"
SQ   SEQUENCE   34 AA;  3457 MW;  081F434A016D339E CRC64;
     TGPQTTCQAS TCEAGCKQIG KSMKSCQGDT CECA