复合体中DNA聚合酶的独立和随机作用
James E Graham1, Kenneth J Marians2, Stephen C Kowalczykowski1
1Department of Microbiology and Molecular Genetics and Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616, USA.
Cell
|June 17, 2017
概括
反复体中的DNA聚合酶独立运作,不需要协调合成. 这种动态过程通过随机暂停和速率切换而不是严格的同步来确保完整的DNA复制.
科学领域:
- 分子生物学
- 遗传学
- 生物化学
背景情况:
- 负责DNA复制的replisome之前被认为需要在领先和落后链DNA聚合酶之间进行严格的协调.
- 这种协调被认为是必要的,以防止在复制过程中新合成的DNA链中出现显著的差距.
研究的目的:
- 在单个复制体内研究领先和落后链DNA聚合酶之间的功能协调.
- 阐明在复制过程中控制DNA合成速率和聚合酶-酶相互作用的动态机制.
主要方法:
- 使用实时单分子分析观察DNA聚合酶活性.
- 在现场跟踪个体DNA聚合酶轨迹和合成速率.
主要成果:
- 领先和滞后链DNA聚合酶在同一复制体内独立运作.
- 单个聚合酶表现出合成速率的随机切换和明显的暂停事件.
- 一个涉及降低酶速度 (∼80%) 的自律机制允许聚合酶在暂停后重新合.
结论:
- DNA复制是一个动力学上不连续的过程,不断地破坏和改造复制体接触.
- 复制体组件的随机行为确保了完全的DNA重复,而无需直接协调链合成.
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