Mechanism of RecA-mediated homologous recombination revisited by single molecule nanomanipulation
Mechanism of RecA-mediated homologous recombination revisited by single molecule nanomanipulation
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DOI：
10.1038/sj.emboj.7601260
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发表时间：
2006-09-20
期刊：
影响因子：
11.4
通讯作者：
Viovy, Jean-Louis
中科院分区：
文献类型：
--
作者：
Fulconis, Renaud;Mine, Judith;Viovy, Jean-Louis
使用磁镊在单分子水平上研究 RecA 介导的三链同源重组机制。探测 DNA 分子和核蛋白丝在张力和扭转下的机械响应，可以从 RecA 结合的单链 DNA 和裸露双链 DNA (dsDNA) 的角度实时监测交换的进展。我们证明链交换甚至能够沿着具有自由旋转末端的分子产生扭转。 RecA 在反应过程中很容易解聚，这一过程为细胞的“蛋白质经济”和拓扑约束的管理带来了许多优势。核蛋白丝侵入未扭曲的 dsDNA 会产生交换的双链体，该双链体在拓扑上仍与交换的单链相连，表明同一分子上链交换的多次起始。总的来说，我们的结果似乎支持单体再分布模型的几个重要假设。
The mechanisms of RecA-mediated three-strand homologous recombination are investigated at the single-molecule level, using magnetic tweezers. Probing the mechanical response of DNA molecules and nucleoprotein filaments in tension and in torsion allows a monitoring of the progression of the exchange in real time, both from the point of view of the RecA-bound single-stranded DNA and from that of the naked double-stranded DNA (dsDNA). We show that strand exchange is able to generate torsion even along a molecule with freely rotating ends. RecA readily depolymerizes during the reaction, a process presenting numerous advantages for the cell's 'protein economy' and for the management of topological constraints. Invasion of an untwisted dsDNA by a nucleoprotein filament leads to an exchanged duplex that remains topologically linked to the exchanged single strand, suggesting multiple initiations of strand exchange on the same molecule. Overall, our results seem to support several important assumptions of the monomer redistribution model.