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Background
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Kaliotoxin-1 has been isolated from the venom of the Scorpion Androctonus mauretanicus mauretanicus. Kaliotoxin-1 is a potent inhibitor of large conductance calcium-activated potassium channels (BK-Ca). This toxin also binds to the dendrotoxin sensitive voltage-dependent potassium channel. It appears to block channel activity by a simple bimolecular inhibition process. Kaliotoxin-1 induces atransient period of fast flickering in the channel openings, followed by an almost complete blockage of the channel. Its binding affinity to rat brain synaptosomes is 5-fold higher than that of KTX-3. Binding of the toxin to the channel is associated with significant structural rearrangements in both molecules.
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