title: Primary structure of a potassium channel toxin from the sea anemone Actinia equina.
abstract: A potassium channel toxin (AeK) was isolated from the sea anemone Actinia equina by gel filtration on Sephadex G-50 and reverse-phase HPLC on TSKgel ODS-120T. AeK and alpha-dendrotoxin inhibited the binding of 125I-alpha-dendrotoxin to rat synaptosomal membranes with IC50 of 22 and 0.34 nM, respectively, indicating that AeK is about sixty-five times less toxic than alpha-dendrotoxin. The complete amino acid sequence of AeK was elucidated; it is composed of 36 amino acid residues including six half-Cys residues. The determined sequence showed that AeK is analogous to the three potassium channel toxins from sea anemones (BgK from Bunodosoma granulifera, ShK from Stichodactyla helianthus and AsKS from Anemonia sulcata), with an especially high sequence homology (86%) with AsKS.
authors.affiliation: Department of Food Science and Technology, Tokyo University of Fisheries, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Minagawa
authors.forename: M
authors.initials: M
authors.lastname: Ishida
authors.forename: Y
authors.initials: Y
authors.lastname: Nagashima
authors.forename: K
authors.initials: K
authors.lastname: Shiomi
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003064:Cnidarian Venoms / Q000737:chemistry*; D008969:Molecular Sequence Data; D010455:Peptides; D026902:Potassium Channel Blockers; D011506:Proteins / Q000737:chemistry / Q000302:isolation & purification*; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
chemical_list: C112490:Aek toxin; D003064:Cnidarian Venoms; D010455:Peptides; D026902:Potassium Channel Blockers; D011506:Proteins