一个Orc6 tether在复制起源许可期间调解ORC绑定站点切换.
David Driscoll1,2, Larry J Friedman2,3, Jeff Gelles3
1HHMI, Cambridge, MA 02139.
概括
原始识别复合体 (ORC) 使用Orc6在DNA复制启动过程中绑定Mcm2-7螺旋酶. 这种相互作用确保一个ORC有效地加载两个酶,防止其释放,并使细胞分裂成为可能.
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:
- 启动DNA复制是细胞分裂的一个基本过程.
- 原始识别复合体 (ORC) 和Mcm2-7螺旋酶对于加载复制机器至关重要.
- 建议使用单个ORC来加载在复制起源的两个Mcm2-7酶.
研究的目的:
- 为了阐明一个ORC如何加载两个Mcm2-7螺旋酶的分子机制.
- 为了研究Orc6在螺旋酶加载过程中的作用.
- 了解CDK酸化如何影响原产地许可期间的ORC功能.
主要方法:
- 单分子福斯特共振能量转移 (smFRET) 试验.
- 在Orc6.6的位点定向突变发生.
- 生物化学测定用于监测ORC-Mcm2-7相互作用.
主要成果:
- 在ORC的绑定位置的过渡期间,Orc6的N终端区域充当了连接线,将ORC连接到Mcm2.
- 这种绑定相互作用对于防止ORC释放到溶液和稳定的双六合体形成至关重要.
- ORC的CDK酸化破坏了Orc6连接相互作用,抑制了Mcm2-7双六合体的形成.
- 在Orc6链接区域的突变可以支持MO复合体的形成,但会损害后续的Mcm2-7招募.
结论:
- 在原产地许可的多个阶段中,Orc6发挥着至关重要的作用,在一个ORC螺旋酶加载机制中作为分子.
- Orc6-Mcm2相互作用为Mcm2-7双六合体的高效和顺序加载提供了分子解释.
- 通过CDK化调节Orc6连接相互作用,可以了解DNA复制启动的细胞周期控制.
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