Structural basis for the poisonous activity of a predator's venom insulin

A potent toxin present in the venom of a fish-hunting cone snail is a minimized insulin (Con-Ins G1) lacking key residues involved in the receptor binding of most insulins. New data show that Con-Ins G1 nevertheless binds potently to the human insulin receptor, owing to a rearrangement that compensates for the lack of a critical binding residue.