Study On The Interaction Between Fipronil And Insect GABA Receptor

γ-Aminobutyric adic(GABA) receptor is the concerned target for many insecticides,and Fipronil(Brand name Regent) is a phenylpyrazole insecticides acting on GABA receptor, so this paper selected as the research object of housefly,herein the fluorescent-labeled ligand and the molecular simulation method were used to study the interactions between the GABA receptor of the insects and fipronil. From two aspects of experiment and theory, it is proved that the high toxicity of fipronil to the insects is of great significance to the development of high efficiency and green pesticides. The contents and results of this paper are as follows:1、the fluorescence complexes FITC- Fipronil were successfully prepared and characterized by XPS.The fluorescence labeling experiment results showed that strong interactions were existed between fipronil and the GABA receptor in the brain of the housefly. The maximum number of binding site [RT] and the equilibrium dissociation constants(Kd) were 21.3±2.5(pmol/ mg protein) and 109±9(nmol/L),respectively.The experiment results clearly illustrated that the fipronil has strong affinity on the GABA receptor of insects and high toxicity to insects.2、The three-dimensional models of the transmembrane domain of Fruitfly RDL receptor were constructed by homology modeling based on the nicotinic acetylcholine receptor.Then Molecular docking and Molecular dynamics were used to investigate the compound of the RDL receptor-fipronil. The molecular simulation results suggested that the model was reasonable. In addition, the compound of the RDL receptor-fipronil was very stable. The theory results clearly illustrated that the fipronil has strong affinity on the GABA receptor of insects and high toxicity to insects.3、Select 1,4-butanediol diglycidyl as activator and directly connected on Sepharose CL-6B and used ammonia ammonification it. Then the fipronil derivatives fixed in Sepharose CL-6B. To simplify the steps of synthesis of medium, high yield,the first successful use of Fipronil in housefly brain GABA receptor purified by affinity column separation.4、Nonionic surfactant NP-40 was used to dissolve GABA receptor protein of housefly brain,we found that protein amout eluted by it was 730ug/m L,which proved to be more than others.5、The received affinity chromatography media was transported to a column, and used it for the the separation and purification of GABA receptor from housefly brain.SDS-PAGE image showed three band, molecular weight at 45 kD, 50 kD and 80 kD respectively.