delta-Palutoxin

delta-Palutoxins (δ-palutoxins) consist of a homologous group of four insect-specific toxins from the venom of the spider Pireneitega luctuosa (also known as Paracoelotes luctuosus).

They show a high toxicity against Spodoptera litura larvae by inhibiting sodium channels, leading to strong paralytic activity and eventually to the death of the insect.

[3] These bindings result in a disulfide pseudo-knot, characteristic for a class of toxins that contain the ‘inhibitor cystine knot motif’ (ICK).

[3] Members of the ICK family are characterized by a triple-stranded, antiparallel β-sheet structure, stabilized by disulfide bridges.

[2] The structural basis for the selectivity of these toxins for insects over the mammalian sodium ion channels is still largely unknown.