MCM2-7环关闭涉及到Mcm5的C端,并触发了Mcm4的ATP水解
Sarah V Faull1, Marta Barbon1,2, Audrey Mossler1
1DNA Replication Group, Institute of Clinical Science, Imperial College London, London, UK.
Nature communications
|January 2, 2025
概括
在MCM2-7中,螺旋酶负荷需要环闭和ATP水解. Mcm4 ATPase活性是调节复制前复合组合的关键,稳定的Mcm2/Mcm5接口是必不可少的.
科学领域:
- 分子生物学分子生物学
- 细胞生物学 细胞生物学
- 生物化学 生物化学
背景情况:
- 细胞MCM2-7酶被ORC,Cdc6和Cdt1加载到复制原点上,形成一个双六合体.
- 将DNA插入MCM2-7会导致部分环闭,而ATP水解对于复制前复合体 (pre-RC) 组装至关重要.
- 控制MCM2-7环闭和ATP水解的机制尚不清楚.
研究的目的:
- 阐明在RC前组装过程中MCM2-7环闭和ATP水解的控制机制.
- 确定关键的ATPase调节酶负载和复合体稳定性的关键ATPase.
主要方法:
- 低温电子显微镜 (cryo-EM) 用于确定ORC-Cdc6-Cdt1-MCM2-7中间体的结构.
- 在Mcm2/Mcm5接口对影响酶负载和稳定性的突变的分析.
- 在螺旋酶加载过程中对Mcm4 ATP水解的研究.
主要成果:
- 一个冷EM结构揭示了一个改造的,完全封闭的Mcm2/Mcm5接口,Mcm5的C端与Orc3.3联系.
- 正常的螺旋酶负载触发了Mcm4 ATP水解,导致MCM2-7复合物的重组和Cdt1的释放.
- 缺陷的Mcm2/Mcm5接口关闭导致MCM2-7环分裂和复杂的拆卸.
结论:
- Mcm4被确定为调节RC前形成的关键ATPase.
- 稳定的Mcm2/Mcm5接口对于依赖ATP水解的MCM2-7重塑和生产性化酶负载至关重要.
- 了解这些机制为DNA复制启动提供了洞察力.
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