关键词: 乳酸乳球菌, PlnF抗菌肽基因, 金黄色葡萄球菌, 分泌表达

Abstract: This study aimed to clone and express the gene encoding antimicrobial peptide PlnF from Lactobacillus plantarum in Lactococcus lactis for the purpose of obtaining a recombinant strain which can be applied directly in in food preservation and preservation. The plnF gene was cloned and inserted into plasmid vector pNZ8149. The resulting recombinant plasmid was transformed by electroporation into competent cells of L. lactis NZ3900 under the conditions: resistance 200 Ω and capacitance 25 μF. The recombinant strain was screened out using a bromocresol purple-supplemented medium, confirmed by PCR and sequenced. The expression was induced by 1 ng/mL nisin for 6 h. The culture supernatant was found to be active against Staphylococcus aureus with an inhibition diameter of (14.03 ± 0.23) mm and it displayed a protein band of 5.8–7.8 kDa as determined by Tricine-SDS-PAGE, which was consistent with the predicted value. Furthermore, the extracellular expression of recombinant PlnF was confirmed by nano LC-ESI-MS/MS.

Key words: Lactococcus lactis, antibacterial peptide PlnF, Staphylococcus aureus, secretory expression