Species marker for developing novel and safe pesticides.

Current anticholinesterase pesticides developed during World War II are toxic to mammals because they target a catalytic serine residue of acetylcholinesterases (AChEs) in insects and in mammals. A sequence analysis of AChEs from 68 species and three-dimensional models of the greenbug and English grain aphid AChEs reported herein reveal that a cysteine residue is present at the active sites of greenbug and aphid AChEs but absent at those of mammalian AChEs. This discovery enables the design of novel and safe pesticides that target the cysteine residue rather than the ubiquitous serine residue.