ID   KA158_MESMA             Reviewed;          60 AA.
AC   Q86BX0;
DT   26-SEP-2003, integrated into UniProtKB/Swiss-Prot.
DT   01-JUN-2003, sequence version 1.
DT   25-MAY-2022, entry version 66.
DE   RecName: Full=Potassium channel toxin alpha-KTx 15.8;
DE   AltName: Full=BmKKx1;
DE   AltName: Full=Neurotoxin Kk4 {ECO:0000312|EMBL:AAP33619.1};
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].
RC   TISSUE=Venom gland;
RX   PubMed=16513212; DOI=10.1016/j.peptides.2006.01.012;
RA   Zeng X.-C., Luo F., Li W.-X.;
RT   "Molecular dissection of venom from Chinese scorpion Mesobuthus martensii:
RT   identification and characterization of four novel disulfide-bridged venom
RT   peptides.";
RL   Peptides 27:1745-1754(2006).
RN   [2]
RP   X-RAY CRYSTALLOGRAPHY (1.78 ANGSTROMS) OF 23-60, FUNCTION, AND SYNTHESIS OF
RP   23-60.
RX   PubMed=29483648; DOI=10.1038/s41594-018-0033-9;
RA   Correnti C.E., Gewe M.M., Mehlin C., Bandaranayake A.D., Johnsen W.A.,
RA   Rupert P.B., Brusniak M.Y., Clarke M., Burke S.E., De Van Der Schueren W.,
RA   Pilat K., Turnbaugh S.M., May D., Watson A., Chan M.K., Bahl C.D.,
RA   Olson J.M., Strong R.K.;
RT   "Screening, large-scale production and structure-based classification of
RT   cystine-dense peptides.";
RL   Nat. Struct. Mol. Biol. 25:270-278(2018).
CC   -!- FUNCTION: Blocker of A-type voltage-gated potassium channels of
CC       cerebellar granular cells. May also inhibit Kv4/KCND when coexpressed
CC       with DPP6 or DPP10. The occlusion of the outer entry of the K(+)
CC       conducting pore is partially reversible and affects both open and
CC       closed channels. It shares the same target in rat brain than BmTX3 (AC
CC       Q8I0L5) and AmmTX3 (AC P60208). Also shows a weak inhibition on
CC       Kv1.2/KCNA2 and Kv1.3/KCNA3 voltage-gated potassium channels
CC       (PubMed:29483648). {ECO:0000250|UniProtKB:P60208,
CC       ECO:0000250|UniProtKB:Q867F4, ECO:0000269|PubMed:29483648}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000305|PubMed:16513212}.
CC   -!- TISSUE SPECIFICITY: Expressed by the venom gland.
CC       {ECO:0000305|PubMed:16513212}.
CC   -!- DOMAIN: Has the structural arrangement of an alpha-helix connected to a
CC       beta-sheet by disulfide bonds (CSalpha/beta).
CC       {ECO:0000269|PubMed:29483648}.
CC   -!- SIMILARITY: Belongs to the short scorpion toxin superfamily. Potassium
CC       channel inhibitor family. Alpha-KTx 15 subfamily. {ECO:0000305}.
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DR   EMBL; AF153692; AAP33619.1; -; mRNA.
DR   PDB; 6AY8; X-ray; 1.78 A; A=23-60.
DR   PDBsum; 6AY8; -.
DR   AlphaFoldDB; Q86BX0; -.
DR   SMR; Q86BX0; -.
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   1: Evidence at protein level;
KW   3D-structure; Disulfide bond; Ion channel impairing toxin; Neurotoxin;
KW   Potassium channel impairing toxin; Pyrrolidone carboxylic acid; Secreted;
KW   Signal; Toxin.
FT   SIGNAL          1..22
FT                   /evidence="ECO:0000255"
FT   CHAIN           23..60
FT                   /note="Potassium channel toxin alpha-KTx 15.8"
FT                   /id="PRO_0000035320"
FT   SITE            49
FT                   /note="Basic residue of the functional dyad"
FT                   /evidence="ECO:0000250"
FT   SITE            58
FT                   /note="Aromatic residue of the functional dyad"
FT                   /evidence="ECO:0000250"
FT   MOD_RES         23
FT                   /note="Pyrrolidone carboxylic acid"
FT                   /evidence="ECO:0000250|UniProtKB:Q8I0L5"
FT   DISULFID        30..50
FT                   /evidence="ECO:0000269|PubMed:29483648,
FT                   ECO:0000312|PDB:6AY8"
FT   DISULFID        35..55
FT                   /evidence="ECO:0000269|PubMed:29483648,
FT                   ECO:0000312|PDB:6AY8"
FT   DISULFID        39..57
FT                   /evidence="ECO:0000269|PubMed:29483648,
FT                   ECO:0000312|PDB:6AY8"
FT   STRAND          24..29
FT                   /evidence="ECO:0007829|PDB:6AY8"
FT   STRAND          31..33
FT                   /evidence="ECO:0007829|PDB:6AY8"
FT   HELIX           36..43
FT                   /evidence="ECO:0007829|PDB:6AY8"
FT   STRAND          44..46
FT                   /evidence="ECO:0007829|PDB:6AY8"
FT   STRAND          48..51
FT                   /evidence="ECO:0007829|PDB:6AY8"
FT   STRAND          54..57
FT                   /evidence="ECO:0007829|PDB:6AY8"
SQ   SEQUENCE   60 AA;  6422 MW;  10095887287E4E56 CRC64;
     MKFSSIILLT LLICSMSIFG NCQVQTNVKC QGGSCASVCR REIGVAAGKC INGKCVCYRN