冈比亚按蚊犬尿氨酸甲酰胺酶抑制剂的虚拟筛选

Virtual screening of inhibitors for kynurenine formamidase of Anopheles gambiae(Diptera:Culicidae)

【目的】利用计算机模拟技术,对冈比亚按蚊Anopheles gambiae犬尿氨酸甲酰胺酶(kynurenine formamidase,KFase)的潜在抑制剂进行虚拟筛选,以获得可以削弱冈比亚按蚊作为中间宿主传播疟疾等蚊媒疾病的候选杀蚊剂。【方法】下载冈比亚按蚊KFase的氨基酸序列,通过BLAST方法查询不同物种中的同源蛋白质,并利用MEGA6最大似然法(maximum likelihood method)构建进化树,选择适于作为模板的同源蛋白黑腹果蝇Drosophila melanogaster KFase晶体结构(PDB ID:4E14),对冈比亚按蚊KFase进行三维建模。利用随机森林算法对小分子化合物数据库进行筛选,并对筛选结果进行处理,模拟自然条件下有机小分子与冈比亚按蚊KFase的结合以及分子对接,从而筛选出冈比亚按蚊KFase的潜在抑制剂。【结果】获得3个小分子化合物与冈比亚按蚊KFase结合的亲和能较低,分别是:N-(2,4-diketo-1H-pyrimidin-6-yl)-2-fluoro-benzamide;3-(4-fluorophenyl)-2,4-dioxo-1,2,3,4-tetrahydropyrimidine-5-carboxylic acid;N-(2-oxo-2,3-dihydro-1Himidazo[4,5-b]pyridin-5-yl)-succinamic acid。它们与冈比亚按蚊KFase结合的亲和能分别为:-9.0,-8.7和-8.9 kcal/mol。【结论】N-(2,4-diketo-1H-pyrimidin-6-yl)-2-fluoro-benzamide,N-(2-oxo-2,3-dihydro-1H-imidazo[4,5-b]pyridin-5-yl)-succinamic acid和3-(4-fluorophenyl)-2,4-dioxo-1,2,3,4-tetrahydropyrimidine-5-carboxylic acid是冈比亚按蚊犬尿氨酸甲酰胺酶的潜在竞争性抑制剂,这些化合物是否可作为杀蚊剂的候选化合物有待实验验证。

【Aim】 To screen potential inhibitors targeting kynurenine formamidase （KFase） of Anopheles gambiae, which could be a candidate insecticide to reduce malaria transmission, by virtual screening. 【Methods】 Protein sequences homologous with KFase of An. gambiae were searched and downloaded from NCBI using BLASTP web server. Phylogenetic tree of homologous proteins was constructed by MEGA6 using maximum likelihood method. Homology modeling of KFase of An. gambiae was performed by SWISS-MODEL web server using KFase of Drosophila melanogaster （PDB ID： 4E14） as a template. The smallmolecule compounds were downloaded from ZINC database and then screened by the method of random forest. Docking analysis of the homology model and selected small molecule compounds was carried out, and the screening results were further validated using molecular dynamics simulation. 【Results】 Three small-molecule compounds, i.e., N-（2,4-diketo-1H-pyrimidin-6-yl）-2-fluoro-benzamide, 3-（4-fluorophenyl）-2,4-dioxo-1,2,3,4-tetrahydropyrimidine-5-carboxylic acid, and N-（2-oxo-2, 3-dihydro-1H-imidazo[4, 5-b] pyridin-5-yl）-succinamic acid, have the lowest docking energy to KFase of An. gambiae with the affinity energy of -9.0, -8.7 and -8.9 kcal/mol, respectively. 【Conclusion】 The three smallmolecule compounds, i.e., N-（2,4-diketo-1H-pyrimidin-6-yl）-2-fluorobenzamide, 3-（4-fluorophenyl）-2,4-dioxo-1,2,3,4-tetrahydropyrimidine-5-carboxylic acid, and N-（2-oxo-2, 3-dihydro-1H-imidazo[4, 5-b] pyridin-5-yl）succinamic acid, could be candidate competitive inhibitors of KFase of An. gambiae. Whether these compounds can be used as candidate mosquitocides needs further experimental validation.