Some assassin bug species are bloodsucking parasites of mammals, even feed on humans.

The toxic saliva of the predatory assassin bugs contains a complex mixture of small and large peptides for diverse uses such as immobilizing and pre-digesting their prey, as well as defense against competitors and predators.

Assassin bug toxins are small peptides with disulfide connectivity that target ion channels.

They are relatively homologous to the calcium channel blockers omega-conotoxins from marine cone snails and belong to the four-loop cysteine scaffold structural class.

Ptu1 contains a beta-sheet region made of 2 antiparallel beta-strands and consists of a compact disulfide-bonded core from which four loops emerge as well as N- and C-termini.