与流动性的双边相互作用可以增强Pol IV介导的TLS
Seungwoo Chang1, Luisa Laureti2, Elizabeth S Thrall1
1Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA.
bioRxiv : the preprint server for biology
|June 10, 2024
概括
DNA聚合酶IV (Pol IV) 与β2过程性的二次相互作用对于通过困难的DNA复制块进行转化合成 (TLS) 是至关重要的. 这种"边缘接触"有助于Pol IV有效地解决停滞不前的复制分叉,减少有害突变.
科学领域:
- 分子生物学分子生物学
- 在DNA复制和修复过程中,
- 生物化学 生物化学
背景情况:
- 渐进性,就像大肠杆菌中的β2一样,对于DNA复制和转化合成 (TLS) 期间的聚合酶切换是必不可少的.
- 这三种大肠杆菌TLS聚合酶都使用一种保留的结基因 (CBM) 与β2的相互作用,这对TLS至关重要.
- 大肠杆菌Pol IV表现出一种独特的二次相互作用,称为二次相互作用.
- 通过非CBM残留物与β2合,其功能意义在很大程度上是未知的.
研究的目的:
- 在转化合成中研究Pol IV和β2流动性之间的二次"边缘接触"的功能作用.
- 为了确定这种边缘接触对不同类型的DNA复制块中Pol IV介导的TLS的重要性.
主要方法:
- 在体外复制试验测试以评估经过定义的DNA损伤 (3-甲基dA和N2-furfuryl dG) 的Pol IV介导的TLS效率.
- 在含有这些DNA病变单个副本的大肠杆菌细胞中进行基因分析,以评估体内TLS性能.
- 对复制分叉动态和在损伤部位的聚合酶竞争的分析.
主要成果:
- 切除Pol IV边缘接触显著损害了经过强大的复制块3-甲基dA的TLS,同时对经过弱块N2-furfuryl dG的TLS产生最小的影响.
- 在体内观察到,在缺乏Pol IV边缘相互作用的大肠杆菌细胞中,在处理强复制阻塞时也存在类似的缺陷.
- 边缘相互作用与ssDNA结合蛋白质相结合,增强了Pol IV与Pol III竞争获取β2的CBM在停滞不前的复制分叉的能力.
结论:
- 二次边缘接触对Pol IV的高效转化合成活动至关重要,特别是在具有挑战性的DNA复制块上.
- 这种双部分互动机制允许Pol IV有效地取代Pol III,并通过TLS解决停滞不前的复制叉.
- 边缘接触和CBM相互作用的合作作用促进了复制分叉的快速TLS,从而最大限度地减少了损伤诱导的突变的产生.
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