Effects of DNA sequence and structure on binding of RecA to single-stranded DNA
Effects of DNA sequence and structure on binding of RecA to single-stranded DNA
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DOI：
10.1073/pnas.151242898
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发表时间：
2001-07-31
影响因子：
11.1
通讯作者：
Libchaber, A
中科院分区：
文献类型：
--
作者：
Bar-Ziv, R;Libchaber, A
荧光各向异性用于跟踪RecA在低DNA和RecA浓度下与短单链DNA（ssDNA）序列（39个碱基）的结合，其中发生聚合的初始阶段。我们观察到RecA缩合对DNA序列的微小变化非常敏感。RecA与富含嘧啶的序列强烈结合，并具有重要的二级结构和碱基堆积。我们发现DNA折叠自由能和RecA结合的起始浓度之间存在相关性。这些结果表明ssDNA的折叠和碱基堆叠代表了RecA结合的障碍。二级结构和结合亲和力之间的联系进一步分析了两个例子：两个自然发生的多态性之间的歧视不同的一个碱基和RecA结合的分子信标。一个自组装模型来解释这些观察。我们建议RecA可用于检测ssDNA序列和结构。
Fluorescence anisotropy is used to follow the binding of RecA to short single-stranded DNA (ssDNA) sequences (39 bases) at low DNA and RecA concentration where the initial phase of polymerization occurs. We observe that RecA condensation is extremely sensitive to minute changes in DNA sequences. RecA binds strongly to sequences that are rich in pyrimidines and that Pack significant secondary structure and base stacking. We find a correlation between the DNA folding free energy and the onset concentration for RecA binding. These results suggest that the folding of ssDNA and base stacking represent a barrier for RecA binding. The link between secondary structure and binding affinity is further analyzed with two examples: discrimination between two naturally occurring polymorphisms differing by one base and RecA binding on a molecular beacon. A self-assembly model is introduced to explain these observations. We propose that RecA may be used to sense ssDNA sequence and structure.