A method of creating crystals of insect acetylcholinesterase. A polynucleotide is obtained that encodes for acetylcholinesterase in a targeted insect. The polynucleotide contains a catalytic core sequence. A recombinant DNA construct is formed by adding a fusion protein and a polyhistidine tag to the catalytic core sequence. The recombinant DNA construct can be further modified by adding known mutations for resistance to insecticides. A growth medium is transfected with the recombinant DNA construct. A polypeptide encoded by the recombinant DNA construct is separated from the growth medium to form a concentrate. The polyhistidine tag is removed from the concentrate. The concentrate is exchanged into a buffer to create a buffered concentrate. Crystals, suitable for X-ray crystallography are then grown with the buffered concentrate.