ID   KAX13_HOTTA             Reviewed;          37 AA.
AC   P24663;
DT   01-MAR-1992, integrated into UniProtKB/Swiss-Prot.
DT   01-FEB-1994, sequence version 2.
DT   25-MAY-2022, entry version 86.
DE   RecName: Full=Potassium channel toxin alpha-KTx 1.3;
DE   AltName: Full=Iberiotoxin {ECO:0000303|PubMed:1694175};
DE            Short=IbTx {ECO:0000303|PubMed:1694175};
OS   Hottentotta tamulus (Eastern Indian scorpion) (Mesobuthus tamulus).
OC   Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Chelicerata; Arachnida;
OC   Scorpiones; Buthida; Buthoidea; Buthidae; Mesobuthus.
OX   NCBI_TaxID=34647;
RN   [1]
RP   PROTEIN SEQUENCE, PYROGLUTAMATE FORMATION AT GLN-1, FUNCTION, AND ACTIVITY
RP   PROFILE.
RC   TISSUE=Venom;
RX   PubMed=1694175; DOI=10.1016/s0021-9258(19)38560-6;
RA   Galvez A., Gimenez-Gallego G., Reuben J.P., Roy-Contancin L.,
RA   Feigenbaum P., Kaczorowski G.J., Garcia M.L.;
RT   "Purification and characterization of a unique, potent, peptidyl probe for
RT   the high conductance calcium-activated potassium channel from venom of the
RT   scorpion Buthus tamulus.";
RL   J. Biol. Chem. 265:11083-11090(1990).
RN   [2]
RP   STRUCTURE BY NMR, AND DISULFIDE BONDS.
RX   PubMed=1381959; DOI=10.1021/bi00150a006;
RA   Johnson B.A., Sugg E.E.;
RT   "Determination of the three-dimensional structure of iberiotoxin in
RT   solution by 1H nuclear magnetic resonance spectroscopy.";
RL   Biochemistry 31:8151-8159(1992).
CC   -!- FUNCTION: Blocks selectively the high conductance calcium-activated
CC       (maxi-K) potassium channels (KCa1.1/KCNMA1).
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   -!- SIMILARITY: Belongs to the short scorpion toxin superfamily. Potassium
CC       channel inhibitor family. Alpha-KTx 01 subfamily. {ECO:0000305}.
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DR   PIR; S32792; S32792.
DR   AlphaFoldDB; P24663; -.
DR   SMR; P24663; -.
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; Pyrrolidone carboxylic acid;
KW   Secreted; Toxin.
FT   PEPTIDE         1..37
FT                   /note="Potassium channel toxin alpha-KTx 1.3"
FT                   /id="PRO_0000044899"
FT   REGION          26..33
FT                   /note="Interaction with Ca(2+)-activated K(+) channels"
FT                   /evidence="ECO:0000255"
FT   SITE            27
FT                   /note="Basic residue of the functional dyad"
FT                   /evidence="ECO:0000250"
FT   SITE            36
FT                   /note="Aromatic residue of the functional dyad"
FT                   /evidence="ECO:0000250"
FT   MOD_RES         1
FT                   /note="Pyrrolidone carboxylic acid"
FT                   /evidence="ECO:0000269|PubMed:1694175"
FT   DISULFID        7..28
FT                   /evidence="ECO:0000269|PubMed:1381959"
FT   DISULFID        13..33
FT                   /evidence="ECO:0000269|PubMed:1381959"
FT   DISULFID        17..35
FT                   /evidence="ECO:0000269|PubMed:1381959"
SQ   SEQUENCE   37 AA;  4254 MW;  012D5EFA710C950E CRC64;
     QFTDVDCSVS KECWSVCKDL FGVDRGKCMG KKCRCYQ