Intrinsic Z-DNA Is Stabilized by the Conformational Selection Mechanism of Z-DNA-Binding Proteins
Intrinsic Z-DNA Is Stabilized by the Conformational Selection Mechanism of Z-DNA-Binding Proteins
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DOI：
10.1021/ja107498y
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发表时间：
2011-02-02
影响因子：
15
通讯作者：
Hohng, Sungchul
中科院分区：
文献类型：
--
作者：
Bae, Sangsu;Kim, Doyoun;Hohng, Sungchul
Z-DNA是沃森和克里克B-DNA的左旋异构体，如果没有高盐浓度或负超卷曲的帮助，Z-DNA很少形成。然而，在生理盐条件下，Z-DNA结合蛋白可以有效地将松弛DNA中的特定B构象序列转化为Z构象。与生物学中许多其他与结构重排相关的特定相互作用一样，这些蛋白质是主动诱导z - dna还是被动捕获瞬时预形成的z - dna一直是一个有趣的问题。在这项研究中，我们使用单分子荧光分析来观察内在的b到z转变，蛋白质的结合/解离事件，以及伴随的b到z转变。结果表明，Z- dna结合蛋白通过有效捕获Z构象而不是主动诱导，动态形成并有效稳定了内源Z- dna。我们的研究首次在单分子水平上提供了内在的b - z转换动力学和蛋白质诱导的b - z转换机制的详细图像。
Z-DNA, a left-handed isoform of Watson and Crick's B-DNA, is rarely formed without the help of high salt concentrations or negative supercoiling. However, Z-DNA-binding proteins can efficiently convert specific sequences of the B conformation into the Z conformation in relaxed DNA under physiological salt conditions. As in the case of many other specific interactions coupled with structural rearrangements in biology, it has been an intriguing question whether the proteins actively induce Z-DNAs or passively trap transiently preformed Z-DNAs. In this study, we used single-molecule fluorescence assays to observe intrinsic B-to-Z transitions, protein association/dissociation events, and accompanying B-to-Z transitions. The results reveal that intrinsic Z-DNAs are dynamically formed and effectively stabilized by Z-DNA-binding proteins through efficient trapping of the Z conformation rather than being actively induced by them. Our study provides, for the first time, detailed pictures of the intrinsic B-to-Z transition dynamics and protein-induced B-to-Z conversion mechanism at the single-molecule level.