On the convergent evolution of animal toxins - conservation of a diad of functional residues in potassium channel-blocking toxins with unrelated structures

M. Dauplais, A. Lecoq, J.X. Song, J. Cotton, N. Jamin, B. Gilquin, E.G. Rowan, C. Vita

Research output: Contribution to journalArticle

287 Citations (Scopus)

Abstract

BgK is a K+ channel-blocking toxin from the sea anemone Bunodosoma granulifera It is a 37-residue protein that adopts a novel fold, as determined by NMR and modeling. An alanine-scanning-based analysis revealed the functional importance of five residues, which include a critical lysine and an aromatic residue separated by 6.6 ± 1.0 Å. The same diad is found in the three known homologous toxins from sea anemones. More strikingly, a similar functional diad is present in all K+ channel-blocking toxins from scorpions, although these toxins adopt a distinct scaffold. Moreover, the functional diads of potassium channel-blocking toxins from sea anemone and scorpions superimpose in the three-dimensional structures. Therefore, toxins that have unrelated structures but similar functions possess conserved key functional residues, organized in an identical topology, suggesting a convergent functional evolution for these small proteins.
Original languageEnglish
Pages (from-to)4302-4309
Number of pages7
JournalJournal of Biological Chemistry
Volume272
Issue number7
DOIs
Publication statusPublished - 14 Feb 1997

Keywords

  • evolution
  • animal toxins
  • conservation
  • diad
  • potassium channel-blocking toxins

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