Overview
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Alomone Labs Pandinotoxin Kα inhibits KV1.2 channels heterologously expressed in Xenopus oocytes.A. Time course of Pandinotoxin Kα (#STP-500) action on KV1.2 currents. KV1.2 currents were elicited by 100 ms voltage ramp from the holding potential of -80 mV to +10 mV. 10 nM and 100 nM Pandinotoxin Kα were perfused as indicated by the bars at -10 mV. B. Superimposed examples of KV1.2 channel current in the absence (control) and presence of 10 nM or 100 nM Pandinotoxin Kα (taken from the experiment in A).
Scorpion venoms are a rich source of ion channel modulators. The scorpion toxins have been useful molecules in probing the K+ channel structures and functions1.
Pandinotoxin Kα (PiTx-Kα) is a 35 amino acid peptidyl toxin isolated from the Pandinus imperator (Emperor scorpion) venom. It is a highly potent and selective blocker of voltage-activated K+ channels. PiTx-Kα preferentially blocks rapidly inactivating (A-type) K+ channels2. In general, channel inhibitors can be pore blockers or gating modifiers. Pore blockers bind to the channel in 1:1 stoichiometry and plug the pore of the channel impeding the flow of the ionic current. These toxins are small proteins that block the passage of K+ ions by binding at the pore entryway on the extracellular side of the channel, thereby inhibiting the ion flux3. The interactions of toxins with K+ channels are among the strongest and most specific known in protein-protein complexes4.
