Assassin bug toxin (IPR012325)

Short name: Assassin_bug_toxin

Overlapping homologous superfamilies


Family relationships



Assassin bugs (Arthropoda:Insecta:Hemiptera:Reduviidae), sometimes known as conenoses or kissing bugs, are one of the largest and morphologically diverse families of true bugs feeding on crickets, caterpillars and other insects. Some assassin bug species are bloodsucking parasites of mammals, even of human. They can be commonly found throughout most of the world and their size varies from a few millimetres to as much as 3 or 4 centimetres. 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, and defence against competitors and predators. Assassin bug toxins are small peptides with disulphide 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 [PMID: 11423127], [PMID: 11669615].

One of these small proteins, Ptu1, blocks reversibly the N-type calcium channels, but at the same time is less specific for the L- or P/Q-type calcium channels [PMID: 11423127]. Ptu1 is 34 amino acid residues long and is cross-linked by three disulphide bridges. Ptu1 contains a beta-sheet region made of two antiparallel beta-strands and consists of a compact disulphide-bonded core from which four loops emerge as well as N- and C-termini [PMID: 11669615]. Some assassin bug toxins are listed below:

  • Agriosphodrus dohrni (Assassin bug) toxin Ado1.
  • Isyndus obscurus (Assassin bug) toxin Iob1.
  • Peirates turpis (Assassin bug) toxin Ptu1.

GO terms

Biological Process

GO:0009405 pathogenesis

Molecular Function

GO:0019855 calcium channel inhibitor activity

Cellular Component

GO:0005576 extracellular region

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
PROSITE patterns