Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 76100, Israel.
Mol Cell. 2010 Nov 12;40(3):388-96. doi: 10.1016/j.molcel.2010.10.020.
Homologous recombination facilitates the exchange of genetic material between homologous DNA molecules. This crucial process requires detecting a specific homologous DNA sequence within a huge variety of heterologous sequences. The detection is mediated by RecA in E. coli, or members of its superfamily in other organisms. Here, we examine how well the RecA-DNA interaction is adjusted to its task. By formulating the DNA recognition process as a signal detection problem, we find the optimal value of binding energy that maximizes the ability to detect homologous sequences. We show that the experimentally observed binding energy is nearly optimal. This implies that the RecA-induced deformation and the binding energetics are fine-tuned to ensure optimal sequence detection. Our analysis suggests a possible role for DNA extension by RecA, in which deformation enhances detection. The present signal detection approach provides a general recipe for testing the optimality of other molecular recognition systems.
同源重组促进同源 DNA 分子之间遗传物质的交换。这个关键过程需要在大量的异源序列中检测到特定的同源 DNA 序列。在大肠杆菌中，这种检测是由 RecA 或其他生物体中其超家族的成员介导的。在这里，我们研究了 RecA-DNA 相互作用与其任务的匹配程度。通过将 DNA 识别过程表述为信号检测问题，我们找到了使同源序列检测能力最大化的最佳结合能值。我们发现，实验观测到的结合能几乎是最佳的。这意味着 RecA 诱导的变形和结合能被精细地调整，以确保最佳的序列检测。我们的分析表明，RecA 引起的 DNA 延伸可能在其中发挥作用，通过变形来增强检测。目前的信号检测方法为测试其他分子识别系统的最优性提供了一个通用的方法。
