Activity of the NtrYX two-component system has been associated with important processes in diverse bacteria, ranging from symbiosis to nitrogen and energy metabolism. In the facultative alphaproteobacterium Rhodobacter sphaeroides, loss of the two-component system NtrYX results in increased lipid production and sensitivity to some known cell envelope-active compounds. In this study, we show that NtrYX directly controls multiple properties of the cell envelope. We find that the response regulator NtrX binds upstream of cell envelope genes, including those involved in peptidoglycan biosynthesis and modification and in cell division. We show that loss of NtrYX impacts the cellular levels of peptidoglycan precursors and lipopolysaccharide and alters cell envelope structure, increasing cell length and the thickness of the periplasm. Cell envelope function is also disrupted in the absence of NtrYX, resulting in increased outer membrane permeability. Based on the properties of R. sphaeroides cells lacking NtrYX and the target genes under direct control of this two-component system, we propose that NtrYX plays a previously undescribed, and potentially conserved, role in the assembly, structure, and function of the cell envelope in a variety of bacteria.

中文翻译：

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NtrYX两组分系统调节细菌细胞包膜。

NtrYX两组分系统的活性与多种细菌的重要过程相关，从共生到氮和能量代谢。在兼性的α变形杆菌Rhodobacter sphaeroides，两组分系统NtrYX的丧失导致脂质产生增加，并且对某些已知的细胞包膜活性化合物敏感。在这项研究中，我们表明NtrYX直接控制细胞膜的多个属性。我们发现响应调节剂NtrX结合细胞包膜基因的上游，包括那些参与肽聚糖生物合成和修饰以及细胞分裂的基因。我们表明，NtrYX的损失会影响肽聚糖前体和脂多糖的细胞水平，并改变细胞包膜结构，增加细胞长度和周质的厚度。在没有NtrYX的情况下，细胞包膜功能也会被破坏，导致外膜通透性增加。基于球形红球菌的性质 缺少NtrYX的细胞和直接在此两组分系统控制下的靶基因的细胞，我们认为NtrYX在多种细菌的细胞包膜的组装，结构和功能中起着以前未描述的且可能是保守的作用。