单向的MCM转移远离ORC驱动原产地许可证
Agata Butryn1, Julia F Greiwe1,2, Alessandro Costa3
1Macromolecular Machines Laboratory, The Francis Crick Institute, London, NW1 1AT, UK.
Nature communications
|January 17, 2025
概括
细胞的复制性酶 (MCM) 载荷机制是使用冷EM. 由MCM驱动的ATPase驱动的DNA转移远离起源识别复合体 (ORC) 对于MCM加载至关重要.
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 生物化学
背景情况:
- MCM电机复合体对于真核细胞DNA复制至关重要,它作为装载在DNA上的双六合体而起作用.
- MCM复合体的加载由原产地识别复合体 (ORC),Cdc6和Cdt1介导,形成一个螺旋酶-招募复合体.
- 通过ATP水解完成MCM加载的精确机制在很大程度上是未知的.
研究的目的:
- 为了研究MCM螺旋酶在DNA上加载的机制.
- 描述MCM加载期间的结构中间体和分子相互作用.
- 阐明MCM ATPase活性在加载过程中的作用.
主要方法:
- 使用冷电子显微镜 (cryo-EM) 来确定高分辨率结构.
- 亚丁酸酶死亡的MCM子单元的素指变体被设计成捕获载荷中间体.
- 实验室DNA结合测试和电子显微镜被用来评估突变的影响.
主要成果:
- 解析了与DNA结合的两个不同的MCM复杂结构,代表成熟阶段.
- 在Mcm2和Mcm5中,特定的氨酸指变异稳定了不同的DNA结合相互作用.
- 双重DNA转位由MCM涉及ATPase发针的特定接触,并且突变会损害DNA结合和复杂的形成.
结论:
- 由MCM远离ORC的ATPase驱动的双重DNA转位是MCM加载的一个关键步骤.
- 这项研究揭示了在螺旋酶加载过程中的关键相互作用和构造变化.
- 了解MCM负载对于理解DNA复制调节和潜在的治疗点至关重要.
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