Petukhova G, Stratton S, Sung P
Institute of Biotechnology and Department of Molecular Medicine, University of Texas Health Science Center at San Antonio, 78245, USA.
Nature. 1998 May 7;393(6680):91-4. doi: 10.1038/30037.
The Saccharomyces cerevisiae RAD51 and RAD54 genes are both required for the occurrence of homologous recombination and for the repair of double-stranded DNA breaks. Previous studies have indicated that Rad51 protein, together with the single-stranded DNA-binding factor replication protein A (RPA), can promote the formation of heteroduplex DNA, which is a key intermediate in homologous recombination. Here we report the purification of the Rad54 protein to near homogeneity and the biochemical testing of its molecular function. We find that Rad54 protein possesses a double-stranded DNA-dependent ATPase activity, and that it interacts with the Rad51 protein. Addition of Rad54 protein to reactions containing Rad51 strongly stimulates the rate of pairing between homologous single-stranded and double-stranded DNA molecules. We conclude that Rad54 acts to overcome kinetic impediments that would limit homologous DNA pairing between recombining chromosomes in vivo.
酿酒酵母的RAD51和RAD54基因对于同源重组的发生以及双链DNA断裂的修复都是必需的。先前的研究表明，Rad51蛋白与单链DNA结合因子复制蛋白A（RPA）一起，可以促进异源双链DNA的形成，而异源双链DNA是同源重组中的关键中间体。在此我们报道了将Rad54蛋白纯化至近乎均一状态，并对其分子功能进行了生化测试。我们发现Rad54蛋白具有依赖双链DNA的ATP酶活性，并且它与Rad51蛋白相互作用。将Rad54蛋白添加到含有Rad51的反应中，可强烈刺激同源单链和双链DNA分子之间的配对速率。我们得出结论，Rad54的作用是克服动力学障碍，这些障碍会限制体内重组染色体之间的同源DNA配对。
