Effect of metal ions on lipopeptide secretion from Bacillus subtilis strain FJAT-4: Negative regulation by Ca2+
Effect of metal ions on lipopeptide secretion from Bacillus subtilis strain FJAT-4: Negative regulation by Ca2+
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DOI：
10.1111/jam.15347
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发表时间：
2021-11-09
影响因子：
4
通讯作者：
Zhu, Yujing
中科院分区：
文献类型：
--
作者：
Chen, Meichun;Zheng, Meixia;Zhu, Yujing
目的探讨金属离子对枯草芽孢杆菌FJAT-4产脂肽的影响及Ca 2+的负调控机制。方法和结果采用LC-MS法测定了不同浓度的K+、Na+、Mg 2+和Ca 2+对脂肽的影响，在含K+、Na+和Mg 2+的培养基中，丰霉素和表面活性素的含量分别为116.24-129.80 mg/L和34.03-63.11 mg/L，而在含Ca 2+的培养基中，浓度分别为0.86和0.63 mg/L。高浓度（45 mM）的Ca 2+对菌株FJAT-4的生长没有不利影响，但引起脂肽合成相关基因表达的显著下调，对应于脂肽产量的减少。通过蛋白质组学分析进一步研究了Ca 2+的这种抑制作用。总共有112种蛋白质被上调，524种蛋白质在额外的Ca 2+（45 mM）的存在下被下调。在这些差异表达蛋白中，28个与磷酸转移酶活性相关，42个与激酶活性相关。蛋白质组学研究结果表明，FJAT-4基因fen和srfA操纵子在高钙胁迫下的表达调控可能与ResD/ResE、PhoP/PhoR和DegU/DegS三个双组分信号转导系统水平的改变有关。结论高浓度Ca 2+（45 mM）可引起脂肽合成减少，其机制可能与ResD/ResE、PhoP/PhoR和DegU/DegS三个双组分信号转导系统有关。研究的意义和影响钙对脂肽合成酶基因表达的调节作用可用于优化脂肽的生产。
Aims This study aimed to investigate the effect of metal ions on lipopeptide production by Bacillus subtilis strain FJAT-4 and the mechanism of negative regulation by Ca2+. Methods and Results The quantitative measurement of lipopeptides in response to K+, Na+, Mg2+ and Ca2+ addition was carried out by LC-MS. The contents of fengycin and surfactin varied within the range of 116.24-129.80 mg/L and 34.03-63.11 mg/L in the culture media containing K+, Na+ and Mg2+, while the levels were 0.86 and 0.63 mg/L in the media containing Ca2+. Ca2+ at a high concentration (45 mM) did not adversely affect the growth of strain FJAT-4, but caused significant downregulation of lipopeptide synthesis-related gene expression, corresponding to a decrease in lipopeptide production. This inhibition by Ca2+ was further investigated by proteomic analysis. In total, 112 proteins were upregulated and 524 proteins were downregulated in the presence of additional Ca2+ (45 mM). Among these differentially expressed proteins (DEPs), 28 were related to phosphotransferase activity, and 42 were related to kinase activity. The proteomics results suggested that altered levels of three two-component signal-transduction systems (ResD/ResE, PhoP/PhoR and DegU/DegS) might be involved in the control of expression of the fen and srfA operons of FJAT-4 under high calcium stress. Conclusions The Ca2+ at the high concentration (45 mM) triggers a decrease in lipopeptide production, which might be attributed to the regulation of three two-component signal-transduction systems ResD/ResE, PhoP/PhoR and DegU/DegS. Significance and Impact of the Study The regulatory effect of calcium on the expression of genes encoding lipopeptide synthetases can be applied to optimize the production of lipopeptides.