Heteropodatoxin

Heteropodatoxins are peptide toxins from the venom of the giant crab spider Heteropoda venatoria, which block Kv4.2 voltage-gated potassium channels.

[2] Heteropodatoxins contain an Inhibitor Cystine Knot (ICK) motif, which consist of a compact disulfide-bonded core, from which four loops emerge.

[2] They show sequence similarity to Hanatoxins, which can be isolated from the venom of the Chilean rose tarantula Grammostola rosea.

[3] It shifts the voltage dependence of the activation and the inactivation of the Kv4.3 potassium channel to more positive values.

However, heterpodatoxin-2 did not affect the voltage dependence of the Kv4.1 channel, suggesting that the precise mechanism of block remains to be elucidated,[3] and a role as a pore blocker cannot be excluded.