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两种对氧化回应的LysR型转录因子控制了Agrobacterium tumefaciens的氧化应激反应
Janka J Schmidt1, Vivian B Brandenburg2, Hannah Elders3
1Microbial Biology, Ruhr University Bochum, 44801 Bochum, Germany.
Nucleic acids research
|April 7, 2025
概括
Agrobacterium tumefaciens使用两个关键蛋白质OxyR和LsrB来感知和响应有害的活性氧物种 (ROS). 这种双重系统增强了细菌在宿主环境中的抗氧化压力的生存能力.
科学领域:
- 微生物学 微生物学
- 分子生物学分子生物学
- 生物化学 生物化学
背景情况:
- 病原性细菌在宿主感染期间面临着波动的活性氧物种 (ROS),需要有效的氧化还原传感机制才能生存.
- 像OxyR这样的LysR型转录调节器 (LTTR) 是已知的细菌基氧化还原传感器.
- Rhizobiales 序列也编码了 LsrB,另一个具有潜在氧化还原感应作用的 LTTR.
研究的目的:
- 研究OxyR和LsrB在植物病原体Agrobacterium tumefaciens的氧化防御中的作用.
- 了解LsrB在A. tumefaciens中的氧化还原感应背后的分子机制.
主要方法:
- 使用单个和组合基因删除来评估H2O2敏感性的基因分析.
- 全基因组转录基因组分析 (RNA-seq) 用于在氧化应激下识别共同调节的基因.
- 单粒子冷电子显微镜 (cryo-EM) 用于确定LsrB的结构.
- 在体外醇捕获试验与质谱学相结合,分析囊蛋白修饰.
主要成果:
- OxyR和LsrB的删除突变对过氧化 (H2O2) 的敏感性增加,证实了它们在氧化防御中的作用.
- 发现OxyR和LsrB在H2O2暴露下共同调节重要的抗氧化基因,包括katG.
- 结构分析揭示了LsrB中的两个近接的氨酸对,生物化学分析证实了所有四种氨酸残留物的可逆醇修饰,表明它们参与了氧化还原调节.
结论:
- Agrobacterium tumefaciens利用基于氨酸的氧化还原感应转录因子OxyR和LSRB的双重系统,以获得强大的氧化应激反应.
- 这种协调调节使细菌能够有效地应对宿主和土壤环境中遇到的氧化挑战,这对病原和生存至关重要.
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