1bgk
From Proteopedia
SEA ANEMONE TOXIN (BGK) WITH HIGH AFFINITY FOR VOLTAGE DEPENDENT POTASSIUM CHANNEL, NMR, 15 STRUCTURES
Overview
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 A. 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.
About this Structure
1BGK is a Single protein structure of sequence from Bunodosoma granulifera. Full crystallographic information is available from OCA.
Reference
On the convergent evolution of animal toxins. Conservation of a diad of functional residues in potassium channel-blocking toxins with unrelated structures., Dauplais M, Lecoq A, Song J, Cotton J, Jamin N, Gilquin B, Roumestand C, Vita C, de Medeiros CL, Rowan EG, Harvey AL, Menez A, J Biol Chem. 1997 Feb 14;272(7):4302-9. PMID:9020148 Page seeded by OCA on Fri May 2 11:29:05 2008
