1bgk: Difference between revisions

[[Image:1bgk.gif|left|200px]]

'''SEA ANEMONE TOXIN (BGK) WITH HIGH AFFINITY FOR VOLTAGE DEPENDENT POTASSIUM CHANNEL, NMR, 15 STRUCTURES'''

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.

1BGK is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Bunodosoma_granulifera Bunodosoma granulifera]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1BGK OCA].  

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