ID   K1A_ANEER               Reviewed;          83 AA.
AC   Q0EAE5;
DT   09-JAN-2007, integrated into UniProtKB/Swiss-Prot.
DT   17-OCT-2006, sequence version 1.
DT   03-AUG-2022, entry version 36.
DE   RecName: Full=Kappa-actitoxin-Aer3a {ECO:0000303|PubMed:22683676};
DE            Short=Kappa-AITX-Aer3a {ECO:0000303|PubMed:22683676};
DE   AltName: Full=AnerK {ECO:0000305};
DE   AltName: Full=Potassium channel toxin AETX K {ECO:0000303|PubMed:16905168};
DE   Flags: Precursor;
OS   Anemonia erythraea (Sea anemone).
OC   Eukaryota; Metazoa; Cnidaria; Anthozoa; Hexacorallia; Actiniaria;
OC   Actiniidae; Anemonia.
OX   NCBI_TaxID=48400;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA], PARTIAL PROTEIN SEQUENCE, FUNCTION, AND MASS
RP   SPECTROMETRY.
RX   PubMed=16905168; DOI=10.1016/j.toxicon.2006.07.002;
RA   Hasegawa Y., Honma T., Nagai H., Ishida M., Nagashima Y., Shiomi K.;
RT   "Isolation and cDNA cloning of a potassium channel peptide toxin from the
RT   sea anemone Anemonia erythraea.";
RL   Toxicon 48:536-542(2006).
RN   [2]
RP   NOMENCLATURE.
RX   PubMed=22683676; DOI=10.1016/j.toxicon.2012.05.020;
RA   Oliveira J.S., Fuentes-Silva D., King G.F.;
RT   "Development of a rational nomenclature for naming peptide and protein
RT   toxins from sea anemones.";
RL   Toxicon 60:539-550(2012).
CC   -!- FUNCTION: Inhibits voltage-gated potassium channels (Kv1/KCNA)
CC       (PubMed:16905168). Blocks the binding of dendrotoxin to rat
CC       synaptosomal membrane in a dose-dependent manner (IC(50)=91 nM)
CC       (PubMed:16905168). Inhibits Kv1.1/KCNA1 and Kv1.3/KCNA3 with high
CC       potency (By similarity). {ECO:0000250|UniProtKB:P29187,
CC       ECO:0000269|PubMed:16905168}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000305|PubMed:16905168}.
CC       Nematocyst {ECO:0000305}.
CC   -!- MASS SPECTROMETRY: Mass=3999.3; Method=MALDI;
CC       Evidence={ECO:0000269|PubMed:16905168};
CC   -!- SIMILARITY: Belongs to the sea anemone type 1 potassium channel toxin
CC       family. Type 1a subfamily. {ECO:0000305}.
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DR   EMBL; AB259113; BAF31325.1; -; mRNA.
DR   PDB; 7OD2; NMR; -; A=50-83.
DR   PDBsum; 7OD2; -.
DR   AlphaFoldDB; Q0EAE5; -.
DR   SMR; Q0EAE5; -.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0042151; C:nematocyst; 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.
DR   InterPro; IPR003582; ShKT_dom.
DR   PROSITE; PS51670; SHKT; 1.
PE   1: Evidence at protein level;
KW   3D-structure; Cleavage on pair of basic residues;
KW   Direct protein sequencing; Disulfide bond; Ion channel impairing toxin;
KW   Nematocyst; Neurotoxin; Potassium channel impairing toxin; Secreted;
KW   Signal; Toxin; Voltage-gated potassium channel impairing toxin.
FT   SIGNAL          1..22
FT                   /evidence="ECO:0000255"
FT   PROPEP          23..49
FT                   /evidence="ECO:0000269|PubMed:16905168"
FT                   /id="PRO_0000272029"
FT   PEPTIDE         50..83
FT                   /note="Kappa-actitoxin-Aer3a"
FT                   /evidence="ECO:0000250|UniProtKB:P29187"
FT                   /id="PRO_0000272030"
FT   DOMAIN          51..83
FT                   /note="ShKT"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01005"
FT   SITE            57
FT                   /note="Important residue for binding Kv1.3/KCNA3"
FT                   /evidence="ECO:0000250|UniProtKB:P29187"
FT   SITE            68
FT                   /note="Important residue for binding Kv1.3/KCNA3"
FT                   /evidence="ECO:0000250|UniProtKB:P29187"
FT   SITE            69
FT                   /note="Important residue for binding Kv1.3/KCNA3"
FT                   /evidence="ECO:0000250|UniProtKB:P29187"
FT   SITE            70
FT                   /note="Key residue for binding both Kv1.2/KCNA2 and
FT                   Kv1.3/KCNA3 (occludes the channel pore like a cork in a
FT                   bottle)"
FT                   /evidence="ECO:0000250|UniProtKB:P29187"
FT   SITE            71
FT                   /note="Important residue for binding Kv1.3/KCNA3"
FT                   /evidence="ECO:0000250|UniProtKB:P29187"
FT   DISULFID        51..83
FT                   /evidence="ECO:0000250|UniProtKB:P29187"
FT   DISULFID        60..76
FT                   /evidence="ECO:0000250|UniProtKB:P29187"
FT   DISULFID        65..80
FT                   /evidence="ECO:0000250|UniProtKB:P29187"
SQ   SEQUENCE   83 AA;  9663 MW;  6CB73D418D2C0328 CRC64;
     MKGQMIICLV LIALCMSVVV MAQNLRAEEL EKANPKDERV RSFERNQKRA CKDYLPKSEC
     TQFRCRTSMK YKYTNCKKTC GTC