关键词: 肠膜明串珠菌素, 结构解析, 理化性质, 抗菌机理

Abstract: Mesenterocin ZLG85 is a novel bacteriocin produced by Leuconstoc mesenteroides subsp. mesenteroides ZLG85, isolated from fermented cucumber. The molecular mass, amino acid sequences and secondary structure of mesenterocin ZLG85 were analyzed by liquid chromatography-mass spectrometry, the Edman method and circular dichroism (CD) spectroscopy. Some of its physicochemical properties were calculated by ProParam tool. The antimicrobial mechanism of mesenterocin ZLG85 against Salmonella typhi as a type strain was explored by evaluating its effects on the leakage of ultraviolet (UV)-absorbing materials, trans-membrane electrical potential and cell membrane permeability. Results showed that the molecular mass of mesenterocin ZLG85 was 2 522.5 Da, and its amino acid sequences differed from those of other reported bacteriocins. Anti-parallel structure, β-sheet and random coil were the major secondary structures of mesenterocin ZLG85, accounting for 32.70%, 20.70% and 36.40%, respectively. This bacteriocin had good stability. It could lead to the leakage of UV-absorbing materials at 260 and 280 nm from the bacterial cells, depolarization of trans-membrane electrical potential, and cause pore formation in the cell membrane and consequently increased cell membrane permeability.

Key words: mesenterocin, structure analysis, physicochemical properties, antimicrobial mechanism