Cloning, expression and characterization of two S-ribosylhomocysteine lyases from Lactobacillus plantarum YM-4-3: Implication of conserved and divergent roles in quorum sensing
Cloning, expression and characterization of two S-ribosylhomocysteine lyases from Lactobacillus plantarum YM-4-3: Implication of conserved and divergent roles in quorum sensing
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植物乳杆菌 YM-4-3 中两种 S-核糖基同型半胱氨酸裂解酶的克隆、表达和表征：群体感应中保守和不同作用的含义
DOI：
10.1016/j.pep.2017.12.013
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发表时间：
2018-05-01
影响因子：
1.6
通讯作者：
Luo, Yi-Yong
中科院分区：
文献类型：
--
作者：
Song, Xiao-Dong;Liu, Chen-Jian;Luo, Yi-Yong
群体感应（Quorum sensing，QS）是一种细胞间通讯的方式，通过小的信号分子调控一系列基因的表达，并控制许多细菌物种的多细胞行为。酶S-核糖基高半胱氨酸裂解酶（LuxS）将S-核糖基高半胱氨酸（SRH）转化为4，5-二羟基-2，3-戊二酮（DPD），即种间QS信号分子自诱导物-2（AI-2）的前体。本研究从植物乳杆菌YM-4-3中分离了两个LuxS编码基因lurS 1和luxS 2，并在大肠杆菌BL 21（DE 3）中进行了高效表达和纯化。在LuxS 1或LuxS 2与SRH孵育后，反应产物能够诱导哈氏弧菌BB 170生物发光，清楚地表明LuxS 1和LuxS 2在体外从SRH合成AI-2。Ellmarfs分析结果显示，LuxS 1和LuxS 2的最佳温度分别为45和37摄氏度，它们的活性被几种金属离子和化学试剂刺激或抑制。此外，酶动力学数据显示，LuxSl对底物（SRH）的Km、K-V-max和K-cat值高于LuxS 2。这些结果表明，LuxS 1和LuxS 2介导的QS在温度依赖性的方式，并可能在AI-2的合成中发挥保守的作用，但表现出不同的活动，在响应外部环境压力。据我们所知，本文是第一个报告的两个luxS基因存在于一个细菌基因组和随后的比较阐明他们的功能在Al-2生产。本研究为进一步研究L. plantarum YM-4-3.
Quorum sensing (QS) is a means of cell-to-cell communication that regulates, via small signalling molecules, expression of a series of genes and controls multicellular behaviour in many bacterial species. The enzyme S-ribosylhomocysteine lyase (LuxS) transforms S-ribosylhomocysteine (SRH) into 4, 5-dihydroxy-2, 3-pentanedione (DPD), the precursor of the interspecies QS signalling molecule autoinducer-2 (AI-2). In this study, two LuxS-coding genes, lurS1 and luxS2, with 70% sequence identity were isolated from Lactobacillus plantarum YM-4-3, and overexpressed in Escherichia coli BL21 (DE3), and the protein products were purified successfully. After incubation of LuxS1 or LuxS2 with SRH, the reaction products were able to induce Vibrio harveyi BB170 bioluminescence, clearly demonstrating that both LuxSl and LuxS2 synthesize AI-2 from SRH in vitro. Ellmarfs assay results revealed optimal temperatures for LuxS1 and LuxS2 of 45 and 37 degrees C, respectively, and their activities were stimulated or inhibited by several metal ions and chemical reagents. In addition, enzyme kinetics data showed that K-m,K- V-max and K-cat value of LuxSl for the substrate (SRH) were higher than that of LuxS2. These results suggest that LuxS1 and LuxS2 mediate QS in a temperature-dependent manner and may play conserved roles in AI-2 synthesis but exhibit different activities in response to external environmental stress. To our knowledge, this paper is the first report of two luxS genes present in one bacterial genome and the subsequent comparative elucidation of their functions in Al-2 production. Collectively, our study provides a solid basis for future research concerning the AI-2/LuxS QS system in L. plantarum YM-4-3.