ID   KA11M_MESMA             Reviewed;          64 AA.
AC   B5KF99;
DT   11-JAN-2011, integrated into UniProtKB/Swiss-Prot.
DT   14-OCT-2008, sequence version 1.
DT   03-AUG-2022, entry version 21.
DE   RecName: Full=Potassium channel toxin alpha-KTx J123 {ECO:0000303|PubMed:18571286};
DE   Flags: Precursor;
OS   Mesobuthus martensii (Manchurian scorpion) (Buthus martensii).
OC   Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Chelicerata; Arachnida;
OC   Scorpiones; Buthida; Buthoidea; Buthidae; Mesobuthus.
OX   NCBI_TaxID=34649;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA], FUNCTION, RECOMBINANT EXPRESSION, AND
RP   3D-STRUCTURE MODELING.
RC   TISSUE=Venom gland;
RX   PubMed=18571286; DOI=10.1016/j.peptides.2008.04.021;
RA   Yin S.-J., Yi H., Ma Y., Chen Z., Song H., Wu Y.-L., Cao Z.-J., Li W.-X.;
RT   "Characterization of a new Kv1.3 channel-specific blocker, J123, from the
RT   scorpion Buthus martensii Karsch.";
RL   Peptides 29:1514-1520(2008).
CC   -!- FUNCTION: This recombinant toxin inhibits mammalian voltage-gated
CC       potassium channels Kv1.3/KCNA3 (IC(50)=0.79 nM) and Kv1.2/KCNA2
CC       (IC(50)=26.4 nM). {ECO:0000269|PubMed:18571286}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000305|PubMed:18571286}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC       {ECO:0000305|PubMed:18571286}.
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 11 subfamily. {ECO:0000305}.
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DR   EMBL; EF065675; ABM87940.1; -; mRNA.
DR   AlphaFoldDB; B5KF99; -.
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   3: Inferred from homology;
KW   Disulfide bond; Ion channel impairing toxin; Neurotoxin;
KW   Potassium channel impairing toxin; Secreted; Signal; Toxin;
KW   Voltage-gated potassium channel impairing toxin.
FT   SIGNAL          1..21
FT                   /evidence="ECO:0000255"
FT   CHAIN           22..64
FT                   /note="Potassium channel toxin alpha-KTx J123"
FT                   /id="PRO_0000403913"
FT   DISULFID        30..52
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01209"
FT   DISULFID        37..60
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01209"
FT   DISULFID        41..62
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01209"
SQ   SEQUENCE   64 AA;  6953 MW;  E2BCB774F82D9277 CRC64;
     MNKVYLVAVL VLFLALTINE SNEAVPTGGC PFSDFFCAKR CKDMKFGNTG RCTGPNKTVC
     KCSI