ID   KA163_MESMA             Reviewed;          59 AA.
AC   Q8MQL0;
DT   26-SEP-2003, integrated into UniProtKB/Swiss-Prot.
DT   01-OCT-2002, sequence version 1.
DT   25-MAY-2022, entry version 57.
DE   RecName: Full=Potassium channel toxin alpha-KTx 16.3;
DE   AltName: Full=Charybdotoxin-like toxin 1;
DE   AltName: Full=Kchtx1;
DE            Short=KTX1;
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].
RA   Xiao L.-Y., Zhang S.-T., Yu S.-Z., Dong J.-J.;
RT   "Cloning and expression of a novel specific blocker of Ca2+ activated K+
RT   from Buthus martensii.";
RL   Submitted (JUL-2002) to the EMBL/GenBank/DDBJ databases.
CC   -!- FUNCTION: Blocks calcium-activated potassium channels.
CC   -!- SUBCELLULAR LOCATION: Secreted.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
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 16 subfamily. {ECO:0000305}.
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DR   EMBL; AF520910; AAQ08762.1; -; mRNA.
DR   EMBL; AY129234; AAM98736.1; -; mRNA.
DR   AlphaFoldDB; Q8MQL0; -.
DR   SMR; Q8MQL0; -.
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   SUPFAM; SSF57095; SSF57095; 1.
DR   PROSITE; PS01138; SCORP_SHORT_TOXIN; 1.
PE   2: Evidence at transcript level;
KW   Calcium-activated potassium channel impairing toxin; Disulfide bond;
KW   Ion channel impairing toxin; Neurotoxin; Potassium channel impairing toxin;
KW   Secreted; Signal; Toxin.
FT   SIGNAL          1..22
FT                   /evidence="ECO:0000255"
FT   CHAIN           23..59
FT                   /note="Potassium channel toxin alpha-KTx 16.3"
FT                   /id="PRO_0000035323"
FT   SITE            50
FT                   /note="Basic residue of the functional dyad"
FT                   /evidence="ECO:0000250"
FT   SITE            59
FT                   /note="Aromatic residue of the functional dyad"
FT                   /evidence="ECO:0000250"
FT   DISULFID        30..51
FT                   /evidence="ECO:0000250"
FT   DISULFID        36..56
FT                   /evidence="ECO:0000250"
FT   DISULFID        40..58
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   59 AA;  6483 MW;  A1A1A2C400D48C97 CRC64;
     MKIFSILLVA LIICSISICT EAFGLIDVKC FASSECWIAC KKVTGSVQGK CQNNQCRCY