Common mechanisms of target cell recognition and immunity for class II bacteriocins
Common mechanisms of target cell recognition and immunity for class II bacteriocins
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DOI：
10.1073/pnas.0608775104
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发表时间：
2007-02-13
影响因子：
11.1
通讯作者：
Nes, Ingolf F.
中科院分区：
文献类型：
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作者：
Diep, Dzung B.;Skaugen, Morten;Nes, Ingolf F.
靶细胞识别和生产细胞自我保护（免疫）的机制都是肽细菌素生物学中重要但知之甚少的问题。在本报告中，我们提供了遗传和生化证据，表明乳球菌素 A（一种来自乳酸乳球菌的透化肽细菌素）使用易感细胞的甘露糖磷酸转移酶系统 (man-PTS) 的成分作为靶标/受体。我们提供的实验证据表明，免疫蛋白 LciA 与受体蛋白和细菌素形成牢固的复合物，从而防止细胞被杀死。重要的是，LciA 和 man-PTS 成分（IIAB、IIC 和 IID）之间的复合物似乎涉及一种开关型机制，仅在细菌素存在的情况下才允许复合物形成；否则，在 LciA 和受体蛋白之间没有观察到复合物。 man-PTS 操纵子的删除结合生化研究表明，膜定位组分 IIC 和 IID 的存在足以对乳球菌素 A 敏感以及与 LciA 形成复合物。 man-PTS 的细胞质成分 IIAB 不是生物敏感性或复合物形成所必需的。此外，乳球菌 man-PTS 操纵子的异源表达使得不敏感的清酒乳杆菌对乳球菌素 A 敏感。我们还提供证据表明，不仅乳球菌素 A，其他 II 类肽细菌素（包括乳球菌素 B 和一些李斯特菌活性片球菌素样细菌素）也以易感细胞上的 man-PTS 成分 IIC 和 IID 为目标，并且它们的免疫蛋白涉及类似于生产细胞自我保护的机制。观察到 LciA。
The mechanisms of target cell recognition and producer cell self-protection (immunity) are both important yet poorly understood issues in the biology of peptide bacteriocins. In this report, we provide genetic and biochemical evidence that lactococcin A, a permeabilizing peptide-bacteriocin from Lactococcus lactis, uses components of the mannose phosphotransferase system (man-PTS) of susceptible cells as target/receptor. We present experimental evidence that the immunity protein LciA forms a strong complex with the receptor proteins and the bacteriocin, thereby preventing cells from being killed. Importantly, the complex between LciA and the man-PTS components (IIAB, IIC, and IID) appears to involve an on-off type mechanism that allows complex formation only in the presence of bacteriocin; otherwise no complexes were observed between LciA and the receptor proteins. Deletion of the man-PTS operon combined with biochemical studies revealed that the presence of the membrane-located components IIC and IID was sufficient for sensitivity to lactococcin A as well as complex formation with LciA. The cytoplasmic component of the man-PTS, IIAB, was not required for the biological sensitivity or for complex formation. Furthermore, heterologous expression of the lactococcal man-PTS operon rendered the insensitive Lactobacillus sakei susceptible to lactococcin A. We also provide evidence that, not only lactococcin A, but other class II peptide-bacteriocins including lactococcin B and some Listeria-active pediocin-like bacteriocins also target the man-PTS components IIC and IID on susceptible cells and that their immunity proteins involve a mechanism in producer cell self-protection similar to that observed for LciA.