Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences , Tianjin, China.
University of Chinese Academy of Sciences , Beijing, China.
Appl Environ Microbiol. 2023 Sep 28;89(9):e0090423. doi: 10.1128/aem.00904-23. Epub 2023 Sep 1.
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 . 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 . OxyR binds to the promoter of and and regulates its expression, as revealed via electrophoretic mobility shift assay analysis, real-time quantitative PCR, and reporting systems. Overexpression of and reduced intracellular sulfane sulfur levels by over 30% and 20% in , 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 . 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 and in 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 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 . 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 . This is the first study on the removal of sulfane sulfur in . These results contribute to the understanding of sulfur regulatory mechanisms and may aid in the future optimization of for biosynthesis of sulfur-containing amino acids.
硫氢化物硫，包括氢多硫化物和有机过硫化物，通常在高浓度下对细胞造成损伤。细胞可以通过特定的机制来调节细胞内的硫氢化物硫水平，但这些机制尚不清楚。OxyR 是一种能够感知氧化应激的转录因子，也对硫氢化物硫有反应。在这项研究中，我们发现 OxyR 直接在 中发挥作用来调节硫氢化物硫。OxyR 与 和 的启动子结合，并通过电泳迁移率变动分析、实时定量 PCR 和报告系统来调节其表达。在 中过表达 和 分别使细胞内的硫氢化物硫水平降低了 30%和 20%以上。RNA 测序分析表明，缺乏 OxyR 下调了硫同化途径基因和/或硫转录因子的表达，这可能降低了硫同化的速度。此外，OxyR 还影响了 中 L-半胱氨酸的生物合成。OxyR 过表达菌株 Cg-2 积累了 183mg/L 的 L-半胱氨酸，比对照（142mg/L）增加了约 30%。总之，OxyR 通过控制 和 在 中的表达不仅调节了硫氢化物硫水平，而且还促进了硫同化和 L-半胱氨酸合成途径，为构建含硫氨基酸及其衍生物的强壮细胞工厂提供了一个潜在的目标。
是一种重要的工业微生物，用于生产各种氨基酸。在含硫氨基酸的生产中，细胞不可避免地会积累大量的硫氢化物硫。然而，很少有研究关注 中硫氢化物硫的去除。在这项研究中，我们不仅揭示了 OxyR 对细胞内硫氢化物硫去除的调节机制，还探索了 OxyR 对 中硫同化和 L-半胱氨酸合成途径的影响。这是对 中硫氢化物硫去除的首次研究。这些结果有助于理解硫调节机制，并可能有助于未来优化 用于含硫氨基酸的生物合成。
