ID   KA183_TITDI             Reviewed;          62 AA.
AC   P0C1X6; C9X4J3;
DT   19-SEP-2006, integrated into UniProtKB/Swiss-Prot.
DT   20-APR-2010, sequence version 2.
DT   25-MAY-2022, entry version 38.
DE   RecName: Full=Potassium channel toxin alpha-KTx 18.3;
DE   AltName: Full=Toxin TdK3 {ECO:0000303|PubMed:16705749};
DE   Flags: Precursor;
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   NUCLEOTIDE SEQUENCE [MRNA].
RC   TISSUE=Venom gland;
RX   PubMed=19470401; DOI=10.1016/j.biochi.2009.05.005;
RA   D'Suze G., Schwartz E.F., Garcia-Gomez B.I., Sevcik C., Possani L.D.;
RT   "Molecular cloning and nucleotide sequence analysis of genes from a cDNA
RT   library of the scorpion Tityus discrepans.";
RL   Biochimie 91:1010-1019(2009).
RN   [2]
RP   PROTEIN SEQUENCE OF 27-62, MASS SPECTROMETRY, AND SUBCELLULAR LOCATION.
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   [3]
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: Probable voltage-gated potassium channel inhibitor.
CC       {ECO:0000305|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=3831.4; Method=Electrospray;
CC       Evidence={ECO:0000269|PubMed:16705749};
CC   -!- MISCELLANEOUS: Does not block or only poorly Shaker B and Kv1.3/KCNA3
CC       potassium channels. {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   EMBL; FN392271; CAY61914.1; -; mRNA.
DR   AlphaFoldDB; P0C1X6; -.
DR   SMR; P0C1X6; -.
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; Signal; Toxin;
KW   Voltage-gated potassium channel impairing toxin.
FT   SIGNAL          1..26
FT                   /evidence="ECO:0000269|PubMed:16705749"
FT   PEPTIDE         27..62
FT                   /note="Potassium channel toxin alpha-KTx 18.3"
FT                   /evidence="ECO:0000269|PubMed:16705749"
FT                   /id="PRO_0000249965"
FT   DISULFID        34..53
FT                   /evidence="ECO:0000250|UniProtKB:P60211"
FT   DISULFID        39..58
FT                   /evidence="ECO:0000250|UniProtKB:P60211"
FT   DISULFID        43..60
FT                   /evidence="ECO:0000250|UniProtKB:P60211"
SQ   SEQUENCE   62 AA;  6633 MW;  BD5957FEC1A98FD6 CRC64;
     MHFSGVAFIL ISMVLIGSIF ETTVEAGEGP KSDCKPDLCE AACKDLGKPM DFCKDGTCKC
     KD