ID   KAX3D_MESEU             Reviewed;          37 AA.
AC   P86396;
DT   30-NOV-2010, integrated into UniProtKB/Swiss-Prot.
DT   30-NOV-2010, sequence version 1.
DT   25-MAY-2022, entry version 28.
DE   RecName: Full=Potassium channel toxin alpha-KTx 3.13;
DE   AltName: Full=MeuKTx {ECO:0000303|PubMed:20713119};
OS   Mesobuthus eupeus (Lesser Asian scorpion) (Buthus eupeus).
OC   Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Chelicerata; Arachnida;
OC   Scorpiones; Buthida; Buthoidea; Buthidae; Mesobuthus.
OX   NCBI_TaxID=34648;
RN   [1]
RP   PROTEIN SEQUENCE, FUNCTION, SUBCELLULAR LOCATION, MASS SPECTROMETRY,
RP   DISULFIDE BONDS, AND AMIDATION AT LYS-37.
RC   TISSUE=Venom;
RX   PubMed=20713119; DOI=10.1016/j.biochi.2010.08.003;
RA   Gao B., Peigneur S., Tytgat J., Zhu S.;
RT   "A potent potassium channel blocker from Mesobuthus eupeus scorpion
RT   venom.";
RL   Biochimie 92:1847-1853(2010).
CC   -!- FUNCTION: Blocks voltage-gated potassium channels Kv1.1/KCNA1
CC       (IC(50)=203.15 pM), Kv1.2/KCNA2 (IC(50)=8.92 nM) from rat and human
CC       Kv1.3 KCNA3/KCNA3 (IC(50)=171 pM) potently. At 2 uM, also blocks Shaker
CC       IR and has a moderate effect on rat Kv1.6/KCNA6.
CC       {ECO:0000269|PubMed:20713119}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000269|PubMed:20713119}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland. {ECO:0000305}.
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   -!- MASS SPECTROMETRY: Mass=3980.8; Method=MALDI;
CC       Evidence={ECO:0000269|PubMed:20713119};
CC   -!- MISCELLANEOUS: Has no effect on rat Kv1.4/KCNA4, Kv1.5/KCNA5,
CC       Kv4.1/KCND1 or human Kv11.1/KCNH2 and Kv3.1/KCNC1.
CC       {ECO:0000305|PubMed:20713119}.
CC   -!- SIMILARITY: Belongs to the short scorpion toxin superfamily. Potassium
CC       channel inhibitor family. Alpha-KTx 03 subfamily. {ECO:0000255}.
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DR   AlphaFoldDB; P86396; -.
DR   SMR; P86396; -.
DR   GO; GO:0005576; C:extracellular region; IDA:UniProtKB.
DR   GO; GO:0019870; F:potassium channel inhibitor activity; IDA:UniProtKB.
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   Amidation; Direct protein sequencing; Disulfide bond;
KW   Ion channel impairing toxin; Neurotoxin; Potassium channel impairing toxin;
KW   Secreted; Toxin; Voltage-gated potassium channel impairing toxin.
FT   PEPTIDE         1..37
FT                   /note="Potassium channel toxin alpha-KTx 3.13"
FT                   /evidence="ECO:0000269|PubMed:20713119"
FT                   /id="PRO_0000401114"
FT   MOD_RES         37
FT                   /note="Lysine amide"
FT                   /evidence="ECO:0000269|PubMed:20713119"
FT   DISULFID        7..27
FT                   /evidence="ECO:0000269|PubMed:20713119"
FT   DISULFID        13..32
FT                   /evidence="ECO:0000269|PubMed:20713119"
FT   DISULFID        17..34
FT                   /evidence="ECO:0000269|PubMed:20713119"
SQ   SEQUENCE   37 AA;  3987 MW;  BB90137C7B55D8C8 CRC64;
     VGINVKCKHS GQCLKPCKDA GMRFGKCMNG KCDCTPK