二硫键对Enterocin A抗李斯特菌LIN3活性的影响

摘要

依据Enterocin A的氨基酸序列,设计半胱氨酸替换突变体Enterocin A（C14S）和Enterocin A（C47W）,通过大肠杆菌表达系统获得重组突变体。用还原剂β-巯基乙醇处理MBP-Enterocin A。采用琼脂扩散实验检测重组Enterocin A、突变体及还原产物的抗无害李斯特菌LIN3活性。结果表明：N末端融合部分不含有半胱氨酸的MBP-Enterocin A或His tag-Enterocin A均表现强抗菌活性;而N末端融合部分含有半胱氨酸的GST-Enterocin A,%Based on the amino acid sequence of Enterocin A,two cysteine substitution mutants,Enterocin A（C14S） and Enterocin A（C47W） were designed and obtained in E.coli expression systems.The agar diffusion assay was used to test the anti-Listeria innocua LIN3 activity of the mutants,recombinant Enterocin A and β-mercaptoethanol-reduced recombinant Enterocin A.Recombinant Enterocin A with His-tag at N-terminus revealed stronger antibacterial activity,while GST-Enterocin A revealed a significant decrease in antibacterial activity.The two mutants andβ-mercaptoethanol-reduced recombinant Enterocin A with destroyed disulfide bonds exhibit no detectable antibacterial activity.Therefore,disulfide bonds are essential for the antibacterial activity of Enterocin A.