Targeted chemical wedges reveal the role of allosteric DNA modulation in protein - DNA assembly
Targeted chemical wedges reveal the role of allosteric DNA modulation in protein - DNA assembly
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DOI：
10.1021/cb700258r
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发表时间：
2008-04-01
影响因子：
4
通讯作者：
Ansari, Aseem Z.
中科院分区：
文献类型：
--
作者：
Moretti, Rocco;Donato, Leslie J.;Ansari, Aseem Z.
多蛋白复合物的协同组装源于DNA结构的变构调节以及蛋白质之间的直接分子间接触。这种协同结合在赋予同源盒转录因子（Hox）家族发育转录因子精细的序列特异性方面起着关键作用。一个典型的例子包括Hox蛋白与外显子（Exd）的相互作用，外显子是一种高度保守的DNA结合转录因子。尽管直接相互作用很重要，但间接相互作用对Hox和Exd合作组装的贡献仍未得到解决。在这里，我们使用小凹槽结合聚酰胺作为结构楔子来诱导Exd结合位点内特定碱基步骤的扰动。我们发现DNA结构的变构调节对Exd与DNA的结合贡献了近1.5 kcal/mol，即使在没有直接Hox接触的情况下。与先前的研究相比，序列靶向化学楔子揭示了DNA几何形状在Hox-Exd复合物协同组装中的作用。可编程聚酰胺可以很好地作为一般探针来研究DNA调制在其他蛋白质-DNA复合物的合作和高度特异性组装中的作用。
The cooperative assembly of multiprotein complexes results from allosteric modulations of DNA structure as well as direct intermolecular contacts between proteins. Such cooperative binding plays a critical role in imparting exquisite sequence specificity on the homeobox transcription factor (Hox) family of developmental transcription factors. A well-characterized example includes the interaction of Hox proteins with extradenticle (Exd), a highly conserved DNA binding transcription factor. Although direct interactions are important, the contribution of indirect interactions toward cooperative assembly of Hox and Exd remains unresolved. Here we use minor groove binding polyamides as structural wedges to induce perturbations at specific base steps within the Exd binding site. We find that allosteric modulation of DNA structure contributes nearly 1.5 kcal/mol to the binding of Exd to DNA, even in the absence of direct Hox contacts. In contrast to previous studies, the sequence-targeted chemical wedges reveal the role of DNA geometry in cooperative assembly of Hox-Exd complexes. Programmable polyamides may well serve as general probes to investigate the role of DNA modulation in the cooperative and highly specific assembly of other protein-DNA complexes.