单链DNA结合蛋白与大肠杆菌 YoaA-χ 螺旋酶一起乘坐
Savannah J Weeks-Pollenz1, Matthew J Petrides1, Robert Davis1
1Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL, 32610-0245, USA.
bioRxiv : the preprint server for biology
|July 1, 2024
概括
大肠杆菌 YoaA-χ 螺旋酶复合体和单链DNA结合蛋白 (SSB) 相互作用,增强DNA损伤耐受性. SSB 影响不同DNA结构上的 YoaA-χ 活动,显示出一种新的机械酶-SSB 转位机制.
科学领域:
- 分子生物学分子生物学
- 修复和复制DNA的修复和复制
- 生物化学 生化学
背景情况:
- 大肠杆菌的YohA (XPD/Rad3样酶) 和 χ (DNA聚合酶III子单元) 形成一个复合体 (YohA-χ),对DNA损伤耐受性至关重要.
- 单链DNA结合蛋白 (SSB) 在停滞的复制分叉上积聚,对于耐受AZT等DNA链终结者至关重要,尽管其与yoaa-χ的机制尚不清楚.
研究的目的:
- 为了研究yoaA-χ螺旋酶复合物和SSB之间的体外相互作用.
- 阐明YohA-χ和SSB对DNA损伤耐受性的机制.
主要方法:
- 在体外生化试验中,研究yoaa-χ在各种DNA基质 (悬浮和分叉DNA) 上的螺旋酶活性.
- 综合生化实验来确定SSB相对于yoaa-χ的结合方向.
- 单分子试验观察SSB与YoaA-χ在单链DNA上的动态相互作用和转位.
主要成果:
- YoaA-χ和SSB表现出一种功能相互作用,SSB以基质依赖的方式调节yoa-χ螺旋酶活性.
- SSB 抑制了分叉DNA基板上的 YoaA-χ 活性,但对悬浮基板的影响很小.
- 单分子分析显示,SSB与YoaA-χ一起沿着单链DNA转移,这表明SSB被酶拉动.
结论:
- 这项研究表明,在DNA损伤耐受性方面,yoaA-χ螺旋酶和SSB之间存在一种新的功能相互作用.
- SSB 与 YoaA-χ 的相互作用影响了酶活性,为DNA 修复途径提供了机械洞察力.
- 这项工作提供了第一个证据,证明一种机械酶积极地沿着单链DNA拉动SSB.
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