单分子成像揭示了由DNA转位酶破坏蛋白质的机制
Ilya J Finkelstein1, Mari-Liis Visnapuu, Eric C Greene
1Department of Biochemistry and Molecular Biophysics, Columbia University, New York, New York 10032, USA.
Nature
|November 26, 2010
概括
DNA转位酶 RecBCD 积极地从DNA中移除蛋白质障碍物. 它通过力量压倒蛋白质,在没有特定相互作用的情况下将它们推到一边,揭示了蛋白质驱逐的机制.
科学领域:
- 分子生物学分子生物学
- 生物化学 生物化学
- 结构生物学 结构生物学
背景情况:
- 核酸转位酶在体内在与蛋白质结合的DNA和RNA上起作用.
- 转位酶的一个关键作用是催化蛋白质从核酸中移位.
- 转位酶从DNA中驱逐蛋白质的机制在很大程度上仍未被探索.
研究的目的:
- 阐明蛋白质从DNA中移位的机械基础.
- 为了研究DNA转位酶RecBCD与各种DNA结合蛋白之间的相互作用.
主要方法:
- 使用纳米制造的DNA窗和多色单分子显微镜.
- 在RecBCD和不同的DNA结合蛋白之间可视化实时碰撞.
主要成果:
- 已证明RecBCD破坏了各种蛋白质障碍物,包括RNA聚合酶,乳酸抑制剂和核细胞.
- 在驱逐之前,RecBCD积极推动蛋白质数千个基对,而不会暂停.
- 观察到的干扰发生不论蛋白质定向相对于RecBCD.
结论:
- RecBCD通过直接的化学机械力转导克服了DNA结合的障碍.
- 蛋白质驱逐通过对过渡状态中间体起作用的活性干扰机制发生.
- 对于RecBCD介导的位移,不需要特定的蛋白质-蛋白质相互作用.
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