Molecular mechanism for the accurate recognition of homologous sequences

同源DNA重组在维持基因组完整性和遗传多样性方面发挥着重要作用。虽然RecA/Rad51同源配对蛋白通过atp水解依赖性反应将DNA分子与精确序列匹配，但atp非依赖性配对蛋白不太可能具有这样的功能。为了了解重组功能的分子基础，我们比较了RecA/Rad51和atp非依赖性同源配对蛋白的反应。核磁共振分析表明，同源配对的基本机制是共同的，独立于蛋白质。另一方面，生物化学和拓扑学研究表明，与atp无关的蛋白质产生三联体，而不是RecA/Rad51产生的d环。这些结果提示了两组蛋白在同源重组中的作用。

Homologous DNA recombination plays roles in the maintenance of genome integrity and in genetic diversification. While RecA/Rad51 homologous pairing proteins pairs DNA molecules with an exact sequence matching by an ATP-hydrolysis-dependent reaction, ATP-independent pairing proteins is unlikely to have such a function. To understand the molecular bases of the recombination functions, we compared RecA/Rad51 and ATP-independent homologous pairing proteins in their reactions. NMR analyses indicate that basic mechanisms of homologous pairing are common independent of the proteins. On the other hand, biochemical and topological studies suggest that an ATP-independent protein generates triplexes, instead of D-loops which RecA/Rad51 produces. These results suggest roles of the two groups of the proteins in homologous recombination.