不动杆菌来源酯键水解酶生物信息学分析及PAEs降解机理

Bioinformatics Analysis of Esterase and Degradation Mechanism of PAEs Came from Acinetobacter indicus

从酒醅中分离得到1株降解邻苯二甲酸二丁酯(DBP)的细菌,命名为Aci-17。通过细菌16S rDNA系统发育分析,菌株Aci-17被鉴定为印度不动杆菌(Acinetobacter indicus)。为深入探讨Aci-17降解邻苯二甲酸酯类(PAEs)机理,利用基因重组技术克隆该菌株的酯键水解酶基因Est96,在大肠杆菌中异源表达获得酯键水解酶Est96。试验结果表明,该蛋白具有突出的降解PAEs能力,对邻苯二甲酸二甲酯(DMP)的降解率达到99.996%。生物信息学分析表明:Est96具有水解酶第Ⅳ家族典型保守基序G-X-S-X-G和HGGG氧阴离子孔结构,活性位点为Ser201,理论分子质量40.66 ku。根据Est96与DMP分子对接结果推测氢键、范德华力、Pi-Pi相互作用力及Est96蛋白分子的HGGG氧阴离子孔、GDSAG和HGF 3个结构域与Est96催化功能密切相关。本研究结果对明晰不动杆菌酯键水解酶催化PAEs生物降解机理提供参考。

An efficient di-n-butyl phthalate(DBP)degrading bacterial strain Aci-17 was isolated from the fermentation grain of Baijiu.Based on its 16 S rRNA gene sequence,strain Aci-17 was identified as Acinetobacter indicus sp.The ester bond hydrolase gene in strain Aci-17 was cloned by gene recombination,aimed to gain insight into the mechanism of phthalate ester(PAEs)degradation.The recombinant Est96 protein demonstrated that it exhibits excellent capacity in degrading for PAEs,the degradation rate of dimethyl phthalate(DMP)reached 99.996%.The bioinformatics analysis of sequencing result was systematically performed,the Est96 encoded by gene Est96 which has the typical conserved motif G-X-S-X-G and HGGG,they are belonged to family IV of hydrolases.the Est96 exhibited a predicted molecular weight of 40.66 ku,amino acid residues 201 is the active site.Docking results of Est96 with DMP show the main interaction forces are the hydrogen bond,van der waals force and Pi-Pi interaction.The conserved sequence motif HGGG,GDSAG and HGF affect the hydrolysis of the substrate ester bond,and laid the foundation for the further exploring the mechanism of Acinetobacter esterase-catalyzed biodegradation of PAEs.