对NHEJ机器的PAXX绑定解释了XLF的功能冗余
Murielle Seif-El-Dahan1, Antonia Kefala-Stavridi2, Philippe Frit3
1Institute for Integrative Biology of the Cell (I2BC), Institute Joliot, CEA, CNRS, Université Paris-Saclay, 91198 Gif-sur-Yvette cedex, France.
Science advances
|May 31, 2023
概括
辅助蛋白PAXX在通过非同类末端连接修复DNA双链断裂方面发挥着关键作用. PAXX和XLF一起工作,通过桥接蛋白质二次体来增强DNA修复.
科学领域:
- 分子生物学分子生物学
- 遗传学 是一个遗传学.
- 结构生物学 结构生物学
背景情况:
- 非同类末端连接 (NHEJ) 是修复人类细胞中DNA双链断裂的主要途径.
- 像PAXX (XRCC4和XLF的对应物) 这样的辅助蛋白对于NHEJ的效率和调节至关重要.
- 了解PAXX的结构和功能作用对于理解DNA修复机制至关重要.
研究的目的:
- 阐明PAXX蛋白在非同类末端连接通路中的结构和功能意义.
- 为了研究PAXX,Ku70/80和DNA-PK二次体之间的相互作用.
- 确定PAXX如何促进DNA双链断裂修复.
主要方法:
- 使用高分辨率冷电子显微镜 (cryo-EM) 和X射线晶体学来确定复杂的结构.
- 实验室和细胞测试用于识别关键相互作用残留物和评估蛋白质功能.
- 进行生物化学分析,研究蛋白质-DNA相互作用和复合体形成.
主要成果:
- 高分辨率结构显示PAXX通过Ku80或XLF结合Ku70/80和替代DNA-PK二元体.
- 在体外和细胞环境中,确定了介导Ku70/PAXX相互作用的关键残留物.
- PAXX和XLF被证明同时与Ku结合,在不同的DNA-PK二极管配置中充当桥梁.
- 证明了PAXX和XLF的同时参与,可以增强DNA末端突触和连接.
结论:
- PAXX是非同类末端连接机械的关键结构和功能部件.
- 通过互补的机制,PAXX和XLF合作促进DNA双链断裂的修复.
- 这些发现为DNA修复中的DNA-PK复合体的组装和功能提供了结构性的见解.
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