鼠李糖乳杆菌LGG芳香酯酶的酶学表征与结构分析  

Enzymatic Characterization and Structural Analysis of Arylesterase from Lacticaseibacillus rhamnosus GG

作　　者：李新锋 郭彤彤 李彬春 LI Xinfeng;GUO Tongtong;LI Binchun(Scientific Instrument Center,Shanxi University,Taiyuan 030006,China;Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education,Institute of Biotechnology,Shanxi University,Taiyuan 030006,China)

机构地区：[1]山西大学大型科学仪器中心,山西太原030006 [2]山西大学生物技术研究所,化学生物学与分子工程教育部重点实验室,山西太原030006

出　　处：《食品科学》2023年第8期162-169,共8页Food Science

基　　金：山西省应用基础研究计划项目(201901D111013)。

摘　　要：为获得新型益生菌酯酶资源,通过挖掘鼠李糖乳杆菌(Lacticaseibacillus rhamnosus GG,LGG)的基因组信息,对芳香酯酶LggAE进行基因克隆、表达纯化、酶学表征与结构分析。结果表明:LggAE的最适反应pH值为7.5,在pH 7.0~10.0范围内保持75%以上酶活力,最适反应温度为50℃,偏好水解中链对硝基苯酚酯,最适底物为对硝基苯酚辛酸酯,在40℃条件下具有一定热稳定性,乙二醇可提升LggAE 17.3%酶活力,LggAE耐受二甲基亚砜,在较高盐浓度柠檬酸钠和氯化钠存在下能保持39.1%~71.0%酶活力,脱氧胆酸钠在高温下显著抑制酶活力。结构分析显示LggAE的底物结合口袋呈较小孔洞状,主要由脂肪族氨基酸残基构成。To obtain novel esterases from probiotic bacteria,the genome of the probiotic Lacticaseibacillus rhamnosus GG(LGG)was analyzed,and the arylesterase gene(LggAE)from LGG was cloned and heterologously expressed.The expressed enzyme was subjected to affinity purification for enzymatic characterization and structural analysis.The results revealed that the optimal pH of the arylesterase was 7.5,which maintained more than 70%of its activity at pH 7.0–10.0.The optimal temperature of LggAE was 50℃.LggAE preferentially hydrolyzed medium-chain p-nitrophenol esters,and the most suitable substrate for it was p-nitrophenol octanoate.LggAE was stable at 40℃.The enzymatic activity of LggAE was improved by 17.3%in the presence of ethylene glycol.LggAE was tolerant to DMSO.LggAE retained 39.1%–71.0%of its activity in the presence of sodium citrate or NaCl at high concentrations.The enzymatic activity of LggAE was significantly inhibited by sodium deoxycholate at high temperatures.Structural analysis showed that the substrate binding pocket of LggAE was a small hole mainly composed of aliphatic hydrophobic residues.

关 键 词：芳香酯酶 鼠李糖乳杆菌 酶学表征 结构分析 底物结合口袋 

分 类 号：Q814.2[生物学—生物工程]