ID   KAX23_CENLI             Reviewed;          38 AA.
AC   P45629;
DT   01-NOV-1995, integrated into UniProtKB/Swiss-Prot.
DT   01-NOV-1995, sequence version 1.
DT   25-MAY-2022, entry version 85.
DE   RecName: Full=Potassium channel toxin alpha-KTx 2.3;
DE   AltName: Full=C.1.limpidus toxin 1 {ECO:0000303|PubMed:7998956};
DE            Short=CllTx1 {ECO:0000303|PubMed:7998956};
DE   AltName: Full=Toxin II.10.9.1 {ECO:0000303|PubMed:7998956};
OS   Centruroides limpidus (Mexican scorpion).
OC   Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Chelicerata; Arachnida;
OC   Scorpiones; Buthida; Buthoidea; Buthidae; Centruroides.
OX   NCBI_TaxID=6876;
RN   [1]
RP   PROTEIN SEQUENCE, SUBCELLULAR LOCATION, FUNCTION, AND MASS SPECTROMETRY.
RC   TISSUE=Venom;
RX   PubMed=7998956; DOI=10.1042/bj3040051;
RA   Martin B.M., Ramirez A.N., Gurrola G.B., Nobile M., Prestipino G.,
RA   Possani L.D.;
RT   "Novel K(+)-channel-blocking toxins from the venom of the scorpion
RT   Centruroides limpidus limpidus Karsch.";
RL   Biochem. J. 304:51-56(1994).
RN   [2]
RP   PROTEIN SEQUENCE, AND SUBCELLULAR LOCATION.
RC   TISSUE=Venom;
RX   PubMed=27889600; DOI=10.1016/j.toxicon.2016.11.256;
RA   Cid Uribe J.I., Jimenez Vargas J.M., Ferreira Batista C.V.,
RA   Zamudio Zuniga F., Possani L.D.;
RT   "Comparative proteomic analysis of female and male venoms from the Mexican
RT   scorpion Centruroides limpidus: novel components found.";
RL   Toxicon 125:91-98(2017).
CC   -!- FUNCTION: Inhibitor of voltage-gated potassium channels (Kv). It is
CC       capable of displacing the binding of radio-labeled noxiustoxin (AC
CC       P08815) to rat brain synaptosomes with high affinity (about 100 pM). It
CC       is also capable of inhibiting transient potassium-currents (resembling
CC       I(A)-type currents), in cultured rat cerebellar granule cells. About
CC       50% of the peak currents are reduced by application of a 1.5 uM
CC       solution of this toxin. {ECO:0000269|PubMed:7998956}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:27889600,
CC       ECO:0000269|PubMed:7998956}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC       {ECO:0000305|PubMed:7998956}.
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=4191; Method=Electrospray;
CC       Evidence={ECO:0000269|PubMed:7998956};
CC   -!- MISCELLANEOUS: This toxin is found in the venom of both male and female
CC       C.limpidus. {ECO:0000269|PubMed:27889600}.
CC   -!- SIMILARITY: Belongs to the short scorpion toxin superfamily. Potassium
CC       channel inhibitor family. Alpha-KTx 02 subfamily. {ECO:0000305}.
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DR   PIR; S53330; S53330.
DR   AlphaFoldDB; P45629; -.
DR   SMR; P45629; -.
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   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 2.3"
FT                   /evidence="ECO:0000269|PubMed:27889600,
FT                   ECO:0000269|PubMed:7998956"
FT                   /id="PRO_0000044902"
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;  4197 MW;  8B7E33F71D4AF009 CRC64;
     ITINVKCTSP QQCLRPCKDR FGQHAGGKCI NGKCKCYP