ABSTRACT

Diseases caused by foodborne pathogens have largely promoted the search for natural biopreservatives. We constructed recombinant plasmids pGEX-4 T-1-lacA, pGEX-4 T-1-lacB, and pGEX-4 T-1-lacAB, harboring genes for bacteriocins lactocin (Lac) A, B, and AB, respectively, with protein expression achieved in Escherichia coli BL21 cells. LacAB was purified using a glutathione S-transferase (GST) protein purification kit, and the GST tag was removed using thrombin for a maximum concentration yield of 1.85 mg/mL. LacAB and the combination of LacA and LacB showed better antimicrobial activity than LacA or LacB alone. The antibacterial activity assay indicated that purified LacAB has broad-spectrum and significant antimicrobial activity against Staphylococcus aureus ATCC25923, with a minimum inhibitory concentration of 125 μg/mL. This study is the first, to our knowledge, to demonstrate the antimicrobial activity of LacAB; moreover, it provides an efficient strategy for the production of bacteriocin LacAB, which could be a food preservative candidate.

摘要

由食源性病原体引起的疾病在很大程度上促进了对天然生物防腐剂的搜索。我们构建了重组质粒pGEX-4 T-1-lacA，pGEX-4 T-1-lacB和pGEX-4 T-1-lacAB，它们分别带有细菌素乳球蛋白（Lac）A，B和AB的基因，分别与大肠杆菌BL21细胞中实现的蛋白质表达。使用谷胱甘肽S-转移酶（GST）蛋白纯化试剂盒纯化LacAB，并使用凝血酶去除GST标签，最大浓缩量为1.85 mg / mL。LacAB以及LacA和LacB的组合显示出比单独的LacA或LacB更好的抗菌活性。抗菌活性测定表明，纯化的LacAB具有广谱和对金黄色葡萄球菌的显着抗菌活性。ATCC25923，最低抑制浓度为125μg/ mL。据我们所知，该研究是第一个证明LacAB的抗菌活性的研究。此外，它提供了生产细菌素LacAB的有效策略，它可以作为食品防腐剂。