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对Synechococcus elongatus PCC 794242中的活性氧物种对延长因子Tu的功能调节的结构洞察
Chen Cheng1, Di Lu1, Huili Sun2
1School of Chemical Engineering, Marine and Life Sciences, Dalian University of Technology, Panjin 124221, China; Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Songling Rd 189, Qingdao 266101, China.
International journal of biological macromolecules
|July 6, 2024
概括
反应性氧物种 (ROS) 通过氧化一个关键的氨酸残留物 (C82) 来使蓝藻细菌中的延长因子Tu (EF-Tu) 失活. 结构分析揭示了EF-Tu如何发挥作用.
科学领域:
- 结构生物学 结构生物学
- 光合作用研究研究 光合作用研究
- 蓝藻细菌的新陈代谢
背景情况:
- 延长因子Tu (EF-Tu) 对于修复光系统II (PSII) 在蓝藻细菌中至关重要,蓝藻细菌对反应性氧物种 (ROS) 的光诱导氧化应激敏感.
- 通过ROS调节EF-Tu功能的精确机制,特别是其光敏感性,仍然在很大程度上是未知的.
- 在EF-Tu中C82 (C82S) 的突变已被证明可以减少光抑制,表明C82在光敏感性中的关键作用.
研究的目的:
- 阐明反应性氧物种 (ROS) 关闭延长因子Tu (EF-Tu) 的分子机制.
- 了解在EF-Tu的光敏感性和ROS调节中的氨酸残留在位置82 (C82) 的作用.
- 确定EF-Tu对氧化应激的脆弱性或抵抗性的结构基础.
主要方法:
- 使用X射线晶体学来确定来自Synechococcus elongatus PCC 7942复杂的GDP的野生类型和C82S突变EF-Tu的结构.
- 结构以高分辨率 (1.7 Å 和 2.0 Å) 解析,以便进行详细的原子分析.
- 分析了C82在不同EF-Tu状态中的形态变化和空间定位.
主要成果:
- 野生型EF-Tu的GDP-bound形式采用开放的形状与内部的C82相结合,使其具有抗氧化能力.
- 交换机I和II的形状变化会创建一个道,使C82暴露在闭合形状的ROS中,使其变得脆弱.
- C82S突变阻止了ROS相互作用,减轻了光抑制,并证实了C82作为关键调节元件的作用.
结论:
- 反应性氧物种 (ROS) 通过氧化C82残留物来禁用EF-Tu,特别是当EF-Tu采用闭合形状时.
- C82的空间布局是EF-Tu对ROS反应的关键决定因素,作为一个对氧化还原敏感的开关.
- 这种机制突出了蓝菌中光合作用生物合成的新调节途径,将氧化应激与EF-Tu功能联系起来.
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