K1A_HETMG
ID K1A_HETMG Reviewed; 74 AA.
AC O16846; O97436;
DT 16-MAY-2006, integrated into UniProtKB/Swiss-Prot.
DT 16-MAY-2006, sequence version 2.
DT 25-MAY-2022, entry version 60.
DE RecName: Full=Kappa-stichotoxin-Hmg1a {ECO:0000303|PubMed:22683676};
DE Short=Kappa-SHTX-Hmg1a {ECO:0000303|PubMed:22683676};
DE AltName: Full=Potassium channel toxin HmK {ECO:0000303|PubMed:9298966};
DE Flags: Precursor;
OS Heteractis magnifica (Magnificent sea anemone) (Radianthus magnifica).
OC Eukaryota; Metazoa; Cnidaria; Anthozoa; Hexacorallia; Actiniaria;
OC Stichodactylidae; Heteractis.
OX NCBI_TaxID=38281;
RN [1]
RP NUCLEOTIDE SEQUENCE [MRNA], PROTEIN SEQUENCE OF 40-74, DISULFIDE BONDS,
RP MASS SPECTROMETRY, AND FUNCTION.
RC TISSUE=Tentacle;
RX PubMed=9298966; DOI=10.1021/bi970253d;
RA Gendeh G.S., Young L.C., de Medeiros C.L.C., Jeyaseelan K., Harvey A.L.,
RA Chung M.C.M.;
RT "A new potassium channel toxin from the sea anemone Heteractis magnifica:
RT isolation, cDNA cloning, and functional expression.";
RL Biochemistry 36:11461-11471(1997).
RN [2]
RP NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC TISSUE=Tentacle;
RX PubMed=9414123; DOI=10.1016/s0014-5793(97)01365-3;
RA Gendeh G.S., Chung M.C.M., Jeyaseelan K.;
RT "Genomic structure of a potassium channel toxin from Heteractis
RT magnifica.";
RL FEBS Lett. 418:183-188(1997).
RN [3]
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 (Kv1.2/KCNA2) and
CC facilitates acetylcholine release at the avian neuromuscular junction
CC (PubMed:9298966). Inhibits Kv1.1/KCNA1 and Kv1.3/KCNA3 with high
CC potency (By similarity). {ECO:0000250|UniProtKB:P29187,
CC ECO:0000269|PubMed:9298966}.
CC -!- SUBCELLULAR LOCATION: Secreted {ECO:0000305|PubMed:9298966}. Nematocyst
CC {ECO:0000305}.
CC -!- MASS SPECTROMETRY: Mass=4054.65; Method=Electrospray;
CC Evidence={ECO:0000269|PubMed:9298966};
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; U58107; AAD09480.1; -; mRNA.
DR EMBL; AF020047; AAB97830.1; -; Genomic_DNA.
DR AlphaFoldDB; O16846; -.
DR SMR; O16846; -.
DR TCDB; 8.B.14.1.6; the sea anemone peptide toxin, class 1 (bgk) family.
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 Cleavage on pair of basic residues; Direct protein sequencing;
KW Disulfide bond; Ion channel impairing toxin; Nematocyst; Neurotoxin;
KW Potassium channel impairing toxin; Secreted; Signal; Toxin;
KW Voltage-gated potassium channel impairing toxin.
FT SIGNAL 1..22
FT /evidence="ECO:0000255"
FT PROPEP 23..39
FT /evidence="ECO:0000269|PubMed:9298966"
FT /id="PRO_0000236028"
FT PEPTIDE 40..74
FT /note="Kappa-stichotoxin-Hmg1a"
FT /evidence="ECO:0000269|PubMed:9298966"
FT /id="PRO_0000236029"
FT DOMAIN 42..74
FT /note="ShKT"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU01005"
FT SITE 46
FT /note="Important residue for binding Kv1.3/KCNA3"
FT /evidence="ECO:0000250|UniProtKB:P29187"
FT SITE 59
FT /note="Important residue for binding Kv1.3/KCNA3"
FT /evidence="ECO:0000250|UniProtKB:P29187"
FT SITE 60
FT /note="Important residue for binding Kv1.3/KCNA3"
FT /evidence="ECO:0000250|UniProtKB:P29187"
FT SITE 61
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 62
FT /note="Important residue for binding Kv1.3/KCNA3"
FT /evidence="ECO:0000250|UniProtKB:P29187"
FT DISULFID 42..74
FT /evidence="ECO:0000269|PubMed:9298966"
FT DISULFID 51..67
FT /evidence="ECO:0000269|PubMed:9298966"
FT DISULFID 56..71
FT /evidence="ECO:0000269|PubMed:9298966"
FT CONFLICT 46
FT /note="I -> M (in Ref. 2; AAB97830)"
FT /evidence="ECO:0000305"
SQ SEQUENCE 74 AA; 8469 MW; 30A566FE969FBE7E CRC64;
MKSQMIAAVL LIAFCLCVVV TARMELQDVE DMENGFQKRR TCKDLIPVSE CTDIRCRTSM
KYRLNLCRKT CGSC
