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结合DNA复制起源的起源识别复合物的结构
Ningning Li1, Wai Hei Lam2, Yuanliang Zhai3,4,5
1State Key Laboratory of Membrane Biology, Peking-Tsinghua Center for Life Sciences, School of Life Sciences, Peking University, Beijing, China.
Nature
|July 6, 2018
概括
原始识别复合体 (ORC) 绑定DNA启动复制. 这项研究揭示了ORC如何在复制原点构建DNA,有助于DNA复制启动和真核细胞中螺旋酶加载.
科学领域:
- 分子生物学
- 结构生物学
- 遗传学
背景情况:
- 原始识别复合体 (ORC) 对于启动真核生物中的DNA复制至关重要.
- ORC识别并与称为复制起源的特定DNA序列结合.
- 了解ORC与DNA的相互作用对于理解复制控制至关重要.
研究的目的:
- 确定与原始DNA结合的Saccharomyces cerevisiae ORC的高分辨率结构.
- 阐明ORC识别并与复制来源结合的分子机制.
- 研究ORC如何调节DNA结构以促进复制的启动.
主要方法:
- 使用三安格斯特罗姆冷电子显微镜 (cryo-EM) 可视化ORC-DNA复合体.
- 这项研究重点是Saccharomyces cerevisiae ORC与72个基对原始DNA序列结合.
- 结构分析确定了特定的蛋白质-DNA相互作用和DNA曲事件.
主要成果:
- 六个子单位的ORC环绕着DNA,与酸盐骨干和基进行广泛的相互作用.
- 在ARS共识序列 (ACS) 和B1元素中诱导显著的DNA曲.
- 特定的胺识别涉及Orc1 (小沟) 中的保存图案和Orc4 (大沟) 中的特定物种图案.
- Orc2和Orc5使用插入动图与DNA基相互作用,并在B1位点曲DNA.
结论:
- 在复制起源时,ORC在调节DNA结构方面发挥着保留作用.
- 这些结构变化对于准确的来源选择和随后的螺旋酶加载至关重要.
- 这些发现为真核DNA复制启动的基本过程提供了原子层面的见解.
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