A butterfly effect: highly insecticidal resistance caused by only a conservative residue mutated of drosophila melanogaster acetylcholinesterase.

Acetylcholinesterase (AChE) and its mutation recently emerged as a significant research area, due to its resistance against organophosphate and carbamate insecticides. Residue G265, which is always a conservative residue, mutated to A265 is the most frequent mutant of AChE in Drosophila populations. However, only this mutation caused a 'butterfly effect' that gives high insecticidal resistance. Herein, the models of sensitive strain (Dm-S) and the resistance strain (Dm-R) were constructed, to give a total of 2000 ps molecular dynamics simulation and to reveal the insecticidal resistance mechanism, with implied, the active gorge of Dm-R was much less flexible than that of Dm-S. The "back door" channel was widened to accelerate the detoxication against insecticides by the conformation changing of W83 and I161. All the distances (S238-H480, S238-G150, S238-G151, Y71-M153) in Dm-R became smaller than those in Dm-S, which may deeply influence the binding between the insecticides and DmAChE.