硫磺,多硫化氢和有机过硫化物的统称,经常损害高浓度的细胞。细胞可以通过特定机制调节细胞内硫烷硫水平,但是这些机制在谷氨酸棒杆菌中还不清楚。OxyR是能够感测氧化应激的转录因子,并且还响应于硫烷硫。在这项研究中,我们发现OxyR直接在调节谷氨酸棒杆菌中的硫烷硫中起作用。OxyR结合katA和nrdH的启动子并调节其表达,如通过体外电泳迁移率变化分析所揭示的,实时定量PCR,和报告系统。在谷氨酸棒杆菌中,katA和nrdH的过表达使细胞内硫烷硫水平降低了30%和20%以上,分别。RNA测序分析表明,OxyR的缺乏下调了硫同化途径基因和/或硫转录因子的表达,这可能会降低硫同化的速率。此外,OxyR还影响谷氨酸棒杆菌中L-半胱氨酸的生物合成。OxyR过表达菌株Cg-2积累183mg/L的L-半胱氨酸,与对照组(142mg/L)相比增加了约30%。总之,OxyR不仅通过控制谷氨酸棒杆菌中katA和nrdH的表达来调节硫烷硫水平,而且促进硫同化和L-半胱氨酸合成途径。为构建含硫氨基酸及其衍生物的强大细胞工厂提供了潜在的目标。重要性谷氨酸棒杆菌是用于生产各种氨基酸的重要工业微生物。在含硫氨基酸的生产中,细胞不可避免地积累了大量的硫烷硫。然而,很少有研究集中在谷氨酸棒杆菌中的硫烷硫去除。在这项研究中,我们不仅揭示了OxyR对胞内硫烷硫去除的调控机制,还探讨了OxyR对谷氨酸棒杆菌硫同化和L-半胱氨酸合成途径的影响。这是第一个研究去除谷氨酸棒杆菌中的硫烷硫。这些结果有助于了解硫调节机制,并可能有助于将来优化谷氨酸棒杆菌以生物合成含硫氨基酸。
Sulfane sulfur, a collective term for hydrogen polysulfide and organic persulfide, often damages cells at high concentrations. Cells can regulate intracellular sulfane sulfur levels through specific mechanisms, but these mechanisms are unclear in Corynebacterium glutamicum.
OxyR is a transcription factor capable of sensing oxidative stress and is also responsive to sulfane sulfur. In this study, we found that
OxyR functioned directly in regulating sulfane sulfur in C. glutamicum. OxyR binds to the promoter of katA and nrdH and regulates its expression, as revealed via in vitro electrophoretic mobility shift assay analysis, real-time quantitative PCR, and reporting systems. Overexpression of katA and nrdH reduced intracellular sulfane sulfur levels by over 30% and 20% in C. glutamicum, respectively. RNA-sequencing analysis showed that the lack of
OxyR downregulated the expression of sulfur assimilation pathway genes and/or sulfur transcription factors, which may reduce the rate of sulfur assimilation. In addition,
OxyR also affected the biosynthesis of L-cysteine in C. glutamicum. OxyR overexpression strain Cg-2 accumulated 183 mg/L of L-cysteine, increased by approximately 30% compared with the control (142 mg/L). In summary, OxyR not only regulated sulfane sulfur levels by controlling the expression of katA and nrdH in C. glutamicum but also facilitated the sulfur assimilation and L-cysteine synthesis pathways, providing a potential target for constructing robust cell factories of sulfur-containing amino acids and their derivatives. IMPORTANCE C. glutamicum is an important industrial microorganism used to produce various amino acids. In the production of sulfur-containing amino acids, cells inevitably accumulate a large amount of sulfane sulfur. However, few studies have focused on sulfane sulfur removal in C. glutamicum. In this study, we not only revealed the regulatory mechanism of
OxyR on intracellular sulfane sulfur removal but also explored the effects of OxyR on the sulfur assimilation and L-cysteine synthesis pathways in C. glutamicum. This is the first study on the removal of sulfane sulfur in C. glutamicum. These results contribute to the understanding of sulfur regulatory mechanisms and may aid in the future optimization of C. glutamicum for biosynthesis of sulfur-containing amino acids.