Expanding the insect defensin landscape.

In this issue of Structure, Walker et al.1 determined the NMR structure of a recently discovered defensin, Pp19, from the venom of an assassin bug. This peptide adopts an α-defensin-like structure, which had not been observed in insects before. Unlike mammalian α-defensins, which are generally antimicrobial, Pp19 has insecticidal activity.