ID   KAX2D_CENSU             Reviewed;          38 AA.
AC   P85529;
DT   16-DEC-2008, integrated into UniProtKB/Swiss-Prot.
DT   16-DEC-2008, sequence version 1.
DT   02-SEP-2026, entry version 33.
DE   RecName: Full=Potassium channel toxin alpha-KTx 2.13 {ECO:0000303|PubMed:18786511};
DE   AltName: Full=Toxin Css20 {ECO:0000303|PubMed:18786511};
OS   Centruroides suffusus (Durango bark scorpion).
OC   Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Chelicerata; Arachnida;
OC   Scorpiones; Buthida; Buthoidea; Buthidae; Centruroides.
OX   NCBI_TaxID=6880;
RN   [1]
RP   PROTEIN SEQUENCE, FUNCTION, MASS SPECTROMETRY, SUBCELLULAR LOCATION, AND
RP   ACTIVITY PROFILE.
RC   TISSUE=Venom;
RX   PubMed=18786511; DOI=10.1016/j.bcp.2008.08.018;
RA   Corzo G., Papp F., Varga Z., Barraza O., Espino-Solis P.G.,
RA   Rodriguez de la Vega R.C., Gaspar R., Panyi G., Possani L.D.;
RT   "A selective blocker of Kv1.2 and Kv1.3 potassium channels from the venom
RT   of the scorpion Centruroides suffusus suffusus.";
RL   Biochem. Pharmacol. 76:1142-1154(2008).
CC   -!- FUNCTION: Selective inhibitor of voltage-gated potassium channels,
CC       blocks the Kv1.2/KCNA2 (Kd=1.3 nM) and Kv1.3/KCNA3 (Kd=7.2 nM)
CC       channels. Association and dissociation rates of the toxin are slower
CC       for Kv1.2/KCNA2 than for Kv1.3/KCNA3. {ECO:0000269|PubMed:18786511}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:18786511}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC       {ECO:0000269|PubMed:18786511}.
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:P40755}.
CC   -!- MASS SPECTROMETRY: Mass=4000.3; Method=Electrospray;
CC       Evidence={ECO:0000269|PubMed:18786511};
CC   -!- MISCELLANEOUS: Negative results: does not inhibit the potassium
CC       channels Kv1.1/KCNA1, Kv1.4/KCNA4, Kv1.5/KCNA5, Kv2.1/KCNB1,
CC       Kv11.1/KCNH2, KCa3.1/KCNN4, KCa1.1/KCNMA1 and the sodium channel
CC       Nav1.5/SCN5A. {ECO:0000305|PubMed:18786511}.
CC   -!- SIMILARITY: Belongs to the short scorpion toxin superfamily. Potassium
CC       channel inhibitor family. Alpha-KTx 02 subfamily. {ECO:0000255}.
CC   ---------------------------------------------------------------------------
CC   Copyrighted by the UniProt Consortium, see https://www.uniprot.org/terms
CC   Distributed under the Creative Commons Attribution (CC BY 4.0) License
CC   ---------------------------------------------------------------------------
DR   AlphaFoldDB; P85529; -.
DR   SMR; P85529; -.
DR   GO; GO:0005576; C:extracellular region; EXP:UniProtKB.
DR   GO; GO:0008200; F:ion channel inhibitor activity; IEA:InterPro.
DR   FunFam; 3.30.30.10:FF:000009; Potassium channel toxin alpha-KTx 4.3; 1.
DR   Gene3D; 3.30.30.10; Knottin, scorpion toxin-like; 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; Scorpion toxin-like; 1.
DR   PROSITE; PS01138; SCORP_SHORT_TOXIN; 1.
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..38
FT                   /note="Potassium channel toxin alpha-KTx 2.13"
FT                   /evidence="ECO:0000269|PubMed:18786511"
FT                   /id="PRO_0000358604"
FT   SITE            28
FT                   /note="Basic residue of the functional dyad"
FT                   /evidence="ECO:0000250"
FT   SITE            37
FT                   /note="Aromatic residue of the functional dyad"
FT                   /evidence="ECO:0000250"
FT   DISULFID        7..29
FT                   /evidence="ECO:0000250|UniProtKB:P40755"
FT   DISULFID        13..34
FT                   /evidence="ECO:0000250|UniProtKB:P40755"
FT   DISULFID        17..36
FT                   /evidence="ECO:0000250|UniProtKB:P40755"
SQ   SEQUENCE   38 AA;  4007 MW;  73672C2B221D74A2 CRC64;
     IFINVKCSSP QQCLKPCKAA FGISAGGKCI NGKCKCYP
//