金黄色葡萄球菌噬菌体裂解酶Lys239表达纯化及活性分析OA北大核心CSTPCD

In order to obtain phage lyase of Staphylococcus aureus with high lytic activityy,the entire gene sequence of the sequenced phage was compared in the GenBank database,and the lytic enzyme gene se-quence was excavated.After cloning,the protein was expressed in BL21(DE3)and purified.The Galleria mellonella was selected as a model to simulate bacterial infection in vivo to explore its antibacterial effect.The results showed that the lyase synthesis gene was successfully constructed into the vector pET22b,re-sulting in a recombinant plasmid pET22b-lys239.And the recombinant plasmid was transfected into BL21(DE3)receptive cells to induce its expression.After purification and validation,Lys239 with lysis activity at a concentration of 2 μg/μL was obtained.The results of the bacterial infection test in the body of the Galle-ria mellonella showed that the survival rate of the Lys239 treatment group was significantly higher than that of the control group.The hemolymph load test showed a significant difference between the control group and each treatment group(P＜0.01),and the higher the concentration of Lys239,the more signifi-cance the inhibitory effect on Staphylococcus aureus.The recombinant lysase Lys239 expressed in this study has good antibacterial effects and can be used as a potential new antibacterial agent.