ID   KA281_ISOMC             Reviewed;          54 AA.
AC   R4GUQ3; J3QW30;
DT   13-NOV-2013, integrated into UniProtKB/Swiss-Prot.
DT   24-JUL-2013, sequence version 1.
DT   03-AUG-2022, entry version 22.
DE   RecName: Full=Potassium channel toxin alpha-KTx 28.1;
DE   AltName: Full=Toxin ImKTx104 {ECO:0000303|PubMed:22511981};
DE   Flags: Precursor;
OS   Isometrus maculatus (Lesser brown scorpion) (Scorpio maculatus).
OC   Eukaryota; Metazoa; Ecdysozoa; Arthropoda; Chelicerata; Arachnida;
OC   Scorpiones; Buthida; Buthoidea; Buthidae; Isometrus.
OX   NCBI_TaxID=497827;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA], FUNCTION, STRUCTURE BY NMR OF 28-54, DISULFIDE
RP   BONDS, AND MUTAGENESIS OF ASP-41; LYS-50 AND LYS-52.
RC   TISSUE=Venom gland;
RX   PubMed=22511981; DOI=10.1371/journal.pone.0035154;
RA   Chen Z.Y., Zeng D.Y., Hu Y.T., He Y.W., Pan N., Ding J.P., Cao Z.J.,
RA   Liu M.L., Li W.X., Yi H., Jiang L., Wu Y.L.;
RT   "Structural and functional diversity of acidic scorpion potassium channel
RT   toxins.";
RL   PLoS ONE 7:E35154-E35154(2012).
CC   -!- FUNCTION: Selectively inhibits Kv7.1/KCNQ1 channel (Kd=11.69 uM) and
CC       inhibits Kv1.1/KCNA1, Kv1.2/KCNA2, Kv1.3/KCNA3 with a very low potency.
CC       {ECO:0000269|PubMed:22511981}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000305}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC       {ECO:0000305|PubMed:22511981}.
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   -!- MISCELLANEOUS: Does not show activity on ion channels KCa1.1/KCNMA1,
CC       KCa2.3/KCNN3 and TRPV1. {ECO:0000305|PubMed:22511981}.
CC   -!- SIMILARITY: Belongs to the short scorpion toxin superfamily. Potassium
CC       channel inhibitor family. Alpha-KTx 28 subfamily. {ECO:0000305}.
CC   -!- CAUTION: PubMed:22511981 describes the 3D-structure 2LIX submitted to
CC       PDB as being secreted by Isometrus maculatus (and not by Lychas
CC       mucronatus as indicated in the PDB entry). {ECO:0000305}.
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   EMBL; EU252205; ACD11798.1; -; mRNA.
DR   PDB; 2LIX; NMR; -; A=28-54.
DR   PDBsum; 2LIX; -.
DR   AlphaFoldDB; R4GUQ3; -.
DR   BMRB; R4GUQ3; -.
DR   SMR; R4GUQ3; -.
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   1: Evidence at protein level;
KW   3D-structure; 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..27
FT                   /evidence="ECO:0000255"
FT   PEPTIDE         28..54
FT                   /note="Potassium channel toxin alpha-KTx 28.1"
FT                   /id="PRO_0000424387"
FT   SITE            50
FT                   /note="May block the Kv7.1/KCNQ1 channel pore"
FT   DISULFID        29..46
FT                   /evidence="ECO:0000269|PubMed:22511981,
FT                   ECO:0000312|PDB:2LIX"
FT   DISULFID        35..51
FT                   /evidence="ECO:0000269|PubMed:22511981,
FT                   ECO:0000312|PDB:2LIX"
FT   DISULFID        39..53
FT                   /evidence="ECO:0000269|PubMed:22511981,
FT                   ECO:0000312|PDB:2LIX"
FT   MUTAGEN         41
FT                   /note="D->A: Shows a weak decrease of activity on
FT                   Kv7.1/KCNQ1."
FT                   /evidence="ECO:0000269|PubMed:22511981"
FT   MUTAGEN         50
FT                   /note="K->A: Shows a decrease of activity on Kv7.1/KCNQ1."
FT                   /evidence="ECO:0000269|PubMed:22511981"
FT   MUTAGEN         52
FT                   /note="K->A: Shows a weak decrease of activity on
FT                   Kv7.1/KCNQ1."
FT                   /evidence="ECO:0000269|PubMed:22511981"
FT   HELIX           33..35
FT                   /evidence="ECO:0007829|PDB:2LIX"
FT   STRAND          38..40
FT                   /evidence="ECO:0007829|PDB:2LIX"
FT   STRAND          42..45
FT                   /evidence="ECO:0007829|PDB:2LIX"
SQ   SEQUENCE   54 AA;  6006 MW;  1359935CE4CC39F3 CRC64;
     MNFWVTFIRL IVVLSIVFAF QIAVAKAACV THEDCTLLCY DTIGTCVDGK CKCM