BcsTx3 is a founder of a novel sea anemone toxin family of potassium channel blocker. (23rd August 2013)

• Record Type: Journal Article
• Authors: Orts, Diego J. B.; Moran, Yehu; Cologna, Camila T.; Peigneur, Steve; Madio, Bruno; Praher, Daniela; Quinton, Loic; De, Edwin; Bicudo, José E. P. W.; Tytgat, Jan; de, José C.
• Is Part Of: FEBS journal. Volume 280:Number 19(2013)
• Page Start: 4839
• Page End: 4852
• Publication Date: 2013-08-23
• Subjects: Biochemistry -- Periodicals; Molecular biology -- Periodicals; Pathology, Molecular -- Periodicals; 572
• DOI: 10.1111/febs.12456
• Languages: English
• ISSNs: 1742-464X

Abstract

<abstract abstract-type="main" id="febs12456-abs-0001"> <title> <x xml:space="preserve">Abstract</x> </title> <p>Sea anemone venoms have become a rich source of peptide toxins which are invaluable tools for studying the structure and functions of ion channels. In this work, BcsTx3, a toxin found in the venom of a <italic>Bunodosoma caissarum</italic> (population captured at the Saint Peter and Saint Paul Archipelago, Brazil) was purified and biochemically and pharmacologically characterized. The pharmacological effects were studied on 12 different subtypes of voltage‐gated potassium channels (K_V1.1–K_V1.6; K_V2.1; K_V3.1; K_V4.2; K_V4.3; <italic>h</italic>ERG and Shaker IR) and three cloned voltage‐gated sodium channel isoforms (Na_V1.2, Na_V1.4 and BgNa_V1.1) expressed in <italic>Xenopus laevis</italic> oocytes. BcsTx3 shows a high affinity for Drosophila Shaker IR channels over rKv1.2, hKv1.3 and rKv1.6, and is not active on Na_V channels. Biochemical characterization reveals that BcsTx3 is a 50 amino acid peptide crosslinked by four disulfide bridges, and sequence comparison allowed BcsTx3 to be classified as a novel type of sea anemone toxin acting on K_V channels. Moreover, putative toxins homologous to BcsTx3 from two additional actiniarian species suggest an ancient origin of this newly discovered toxin family.</p> </abstract>