Salinas F, Kodadek T
Department of Chemistry and Biochemistry, University of Texas at Austin 78712-1096, USA.
Cell. 1995 Jul 14;82(1):111-9. doi: 10.1016/0092-8674(95)90057-8.
Homologous strand exchange is a central step in general genetic recombination. A multiprotein complex composed of five purified bacteriophage T4 proteins (the products of the uvsX, uvsY, 32, 41, and 59 genes) that mediates strand exchange under physiologically relevant conditions has been reconstituted. One of these proteins, the product of the uvsY gene, is required for homologous pairing but strongly inhibits branch migration catalyzed by UvsX protein, the phage RecA analog. Branch migration is completely dependent on the gene 41 protein, a DNA helicase that also functions in phage replication. The helicase is delivered to the strand exchange complex by the gene 59 accessory protein in a strand-specific fashion through direct interactions between the gene 59 and gene 32 proteins. These data suggest that strand transferases such as UvsX protein are essential for homologous pairing in vivo, but that a DNA helicase drives polar branch migration.
同源链交换是一般遗传重组的核心步骤。一种由五种纯化的噬菌体T4蛋白（uvsX、uvsY、32、41和59基因的产物）组成的多蛋白复合物已被重组，该复合物在生理相关条件下介导链交换。其中一种蛋白，uvsY基因的产物，是同源配对所必需的，但它强烈抑制由噬菌体RecA类似物UvsX蛋白催化的分支迁移。分支迁移完全依赖于基因41蛋白，一种也在噬菌体复制中起作用的DNA解旋酶。通过基因59和基因32蛋白之间的直接相互作用，基因59辅助蛋白以链特异性方式将解旋酶传递到链交换复合物中。这些数据表明，诸如UvsX蛋白之类的链转移酶在体内同源配对中至关重要，但DNA解旋酶驱动极性分支迁移。
