Characterisation of the action mechanism of a Lactococcus-specific bacteriocin, lactococcin Z
Characterisation of the action mechanism of a Lactococcus-specific bacteriocin, lactococcin Z
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DOI：
10.1016/j.jbiosc.2018.05.018
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发表时间：
2018-11-01
影响因子：
2.8
通讯作者：
Sonomoto, Kenji
中科院分区：
文献类型：
--
作者：
Daba, Ghoson Mosbah;Ishibashi, Naoki;Sonomoto, Kenji
乳球菌素Z是由乳球菌QU7产生的一种新型细菌素，与乳球菌素A有55.6%的同源性。为了鉴定乳球菌素Z的靶向受体，从敏感菌株L乳酸菌IL1403中获得了几个乳球菌素Z抗性突变株。抗性突变体在利用甘露糖和葡萄糖作为唯一碳源方面表现出困难，这与它们在半乳糖作为唯一碳源时的生长模式相反。突变株的ptnc和ptnD基因分别编码甘露糖磷酸转移酶系统(Man-PTS)组分IIC和IID，因此，IIC和HD被认为是乳霉素Z潜在的受体，也是乳霉素A靶向的相同受体。两种乳球菌素A和Z在N-末端有很高的同源性，而C-末端相似性较低，这可能是它们作用机制不同以及它们之间缺乏交叉免疫的原因。尽管乳霉素Z具有杀菌活性，但它既没有消散敏感细胞的膜电位，也没有在敏感细胞的膜上形成气孔，这与形成气孔的乳球素A(C)2018形成了鲜明对比，日本生物技术学会。版权所有。
Lactococcin Z is a novel Lactococcus-specific bacteriocin produced by Lactococcus lactis QU 7 that shares 55.6% identity with lactococcin A. To identify the receptor targeted by lactococcin Z, several lactococcin Z-resistant mutants were generated from the sensitive strain, L lactis IL1403. The resistant mutants showed difficulties in utilising mannose and glucose as sole carbon sources, contrary to their pattern of growth in the presence of galactose as a sole carbon source. Mutations were found in the ptnC and ptnD genes of lactococcin Z-resistant mutants, which encode the mannose phosphotransferase system (Man-PTS) components, IIC and IID, respectively; therefore, IIC and HD are proposed as potential receptors employed by lactococcin Z and are the same receptors targeted by lactococcin A. Both lactococcins A and Z share a high percentage identity in their N-termini regions in contrast to their C-termini that show less similarity; this may explain the difference in their action mechanisms as well as the lack of cross-immunity between them. Although lactococcin Z showed bactericidal activity, it neither dissipated membrane potential nor formed pores on the membranes of sensitive cells, in sharp contrast to the pore-forming lactococcin A. (C) 2018, The Society for Biotechnology, Japan. All rights reserved.