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Abstract：
The antimicrobial peptide LRGG (LLRLLRRGGRRLLRLL-NH2) was designed and chemically synthesized in a study conducted by Jia et al. Gram-negative bacteria were found to be sensitive to LRGG and exhibited a high therapeutic index. Genetic engineering methods were used to create the prokaryotic fusion expression vector pQE-GFP-LRGG, and the resulting corresponding fusion protein GFP-LRGG was subsequently expressed and purified. The precursor GFP was then removed by TEV proteolysis, and pure LRGG was obtained after another round of purification and endotoxin removal. The prokaryotic-expressed antimicrobial peptide LRGG displays a broad-spectrum antibacterial effect on Gram-negative bacteria, and its minimum inhibitory activity (MIC) against Escherichia coli can reach 2 μg/mL. Compared to the chemically synthesized LRGG, the prokaryotic-expressed LRGG exhibits similar temperature, pH, salt ion, serum stability, and cell selectivity. Furthermore, prokaryotic-expressed LRGG showed excellent therapeutic effects in both the infection model of cell selectivity and no embryotoxicity in a Galleria mellonella infection model. The mechanism by which LRGG causes bacterial death was found to be the disruption of the Gram-negative cell membrane.
摘要：
抗微生物肽LRGG（LLRLLRGGRRLLRLLRLL-NH2）是在Jia等人进行的研究中设计和化学合成的。发现革兰氏阴性菌对LRGG敏感，并表现出高治疗指数。采用基因工程方法制备原核融合表达载体pQE-GFP-LRGG,随后表达并纯化得到的相应融合蛋白GFP-LRGG。然后通过TEV蛋白水解去除前体GFP，在另一轮纯化和去除内毒素后获得纯的LRGG。原核表达的抗菌肽LRGG对革兰氏阴性菌具有广谱抗菌作用,其对大肠杆菌的最低抑菌活性(MIC)可达2μg/mL。与化学合成的LRGG相比，原核表达的LRGG表现出相似的温度，pH值,盐离子，血清稳定性，和细胞选择性。此外，原核表达的LRGG在细胞选择性感染模型和无胚胎毒性的Galleriamellonella感染模型中均显示出出色的治疗效果。发现LRGG引起细菌死亡的机制是革兰氏阴性细胞膜的破坏。
