人类CTF18-RFC加载器的结构绑定到PCNA
Giuseppina R Briola1, Muhammad Tehseen1, Amani Al-Amodi1
1Bioscience Program, Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal 23955, Saudi Arabia.
bioRxiv : the preprint server for biology
|August 8, 2025
概括
人类CTF18-RFC复合体,一个关键的DNA加载器,已被结构性地表征. 它的独特特性促进了PCNA的加载,这对于DNA复制和Pol ε介导合成至关重要.
科学领域:
- 分子生物学分子生物学
- 结构生物学 结构生物学
- 生物化学 生化学
背景情况:
- 滑动,如PCNA (增殖细胞核抗原),对于DNA复制忠实性至关重要.
- 片装载器需要将滑动片装载到DNA上,这是对过程性至关重要的过程.
- CTF18-RFC是一种与DNA聚合酶epsilon (Pol ε) 相互作用的替代人类加载器.
研究的目的:
- 从结构上描述人类CTF18-RFC复合体及其与PCNA的相互作用.
- 为了阐明CTF18-RFC将PCNA加载到DNA上的机制.
- 了解CTF18-RFC在刺激Pol ε.领先链DNA合成中的作用.
主要方法:
- 使用冷电子显微镜 (cryo-EM) 来确定CTF18-RFC-PCNA复合物的结构.
- 生物化学测试被用来评估CTF18-RFC在压载荷和DNA合成中的功能.
主要成果:
- 一个2.9 Å的冷-EM结构揭示了CTF18-RFC复合体与PCNA结合在一个自抑制状态.
- Ctf8和Dcc1子单元灵活地连接到RFC模块,与Pol ε相互作用.
- 在Ctf18亚单元的N端处的一个新型β-hairpin对于CTF18-RFC-PCNA复合体的稳定性和功能至关重要.
结论:
- 人类CTF18-RFC复合体具有独特的结构特征,可以将其与正规的加载器区分开来.
- 鉴定到的结构特征为PCNA加载的机制提供了洞察力,由CTF18-RFC.
- CTF18-RFC在刺激Pol ε的领先链合成中发挥着重要作用,突出了其在DNA复制中的重要性.
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