ESCHERICHIA-COLI RUVA-PROTEIN AND RUVB-PROTEIN SPECIFICALLY INTERACT WITH HOLLIDAY JUNCTIONS AND PROMOTE BRANCH MIGRATION
ESCHERICHIA-COLI RUVA-PROTEIN AND RUVB-PROTEIN SPECIFICALLY INTERACT WITH HOLLIDAY JUNCTIONS AND PROMOTE BRANCH MIGRATION
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DOI：
10.1101/gad.6.11.2214
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发表时间：
1992-11-01
影响因子：
10.5
通讯作者：
SHINAGAWA, H
中科院分区：
文献类型：
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作者：
IWASAKI, H;TAKAHAGI, M;SHINAGAWA, H
大肠杆菌ruvA和ruvB基因参与DNA修复和同源遗传重组的后期步骤。我们以前已经证明，RuvA-RuvB蛋白复合物在ATP的存在下，促进从具有反向重复序列的超螺旋质粒中挤出的十字形结构的重吸收。由于十字形结构在拓扑学上类似于霍利迪结构，我们提出RuvA和RuvB蛋白在重组中的作用是促进霍利迪连接处的链交换反应。在这里，我们研究了特定的相互作用的RuvA-RuvB复合物与霍利迪结构使用合成的类似物退火制备的四个寡核苷酸。RuvA蛋白对合成霍利迪连接的亲和力比双链体DNA高得多（>20倍），并且RuvA蛋白对连接的亲和力通过与RuvB蛋白的相互作用进一步增强（>4倍）。在ATP存在下的RuvA-RuvB蛋白复合物通过催化分支迁移到DNA末端，促进在中心核心中具有同源性的合成霍利迪连接解离成两半，但它不影响没有同源性的合成霍利迪连接的结构。合成霍利迪连接的分离是RuvA-RuvB复合物促进链交换和DNA解旋的活性的结果。此外，RuvA和RuvB促进RecA在Holliday连接处的链交换反应。这些结果进一步证明了RuvA-RuvB复合物识别Holliday连接并促进同源重组中的分支迁移。
The Escherichia coli ruvA and ruvB genes are involved in DNA repair and in the late step of homologous genetic recombination. We have demonstrated previously that the RuvA-RuvB protein complex in the presence of ATP promotes reabsorption of cruciform structures extruded from a supercoiled plasmid with an inverted repeat sequence. Because the cruciform structure is topologically analogous to the Holliday structure, we have proposed that the role of the RuvA and RuvB proteins in recombination is to promote a strand exchange reaction at the Holliday junction. Here, we studied the specific interaction of the RuvA-RuvB complex with the Holliday structure using synthetic analogs prepared by annealing four oligonucleotides. The affinities of the RuvA protein for synthetic Holliday junctions are much higher (>20-fold) than for duplex DNA, and the affinities of the RuvA protein for the junctions are further enhanced (>4-fold) by the interaction with the RuvB protein. The RuvA-RuvB protein complex in the presence of ATP promotes dissociation of the synthetic Holliday junction with homology in the central core into two halves by catalyzing branch migration to the DNA ends, but it does not affect the structure of the synthetic Holliday junction without the homology. The separation of the synthetic Holliday junction is a result of the activity of the RuvA-RuvB complex that promotes strand exchange and DNA unwinding. Furthermore, RuvA and RuvB promote the strand exchange reaction at the Holliday junctions made by RecA. These results provide further evidence that the RuvA-RuvB complex recognizes the Holliday junction and promotes branch migration in homologous recombination.