Conformational Heterogeneity in a Fully Complementary DNA Three-Way Junction with a GC-Rich Branchpoint.
Conformational Heterogeneity in a Fully Complementary DNA Three-Way Junction with a GC-Rich Branchpoint.
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DOI：
10.1021/acs.biochem.7b00677
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发表时间：
2017-09
期刊：
影响因子：
2.9
通讯作者：
Anita Toulmin;Laura E. Baltierra-Jasso;Michael J. Morten;T. Sabir;P. McGlynn;G. Schröder;Brian O. Smith;S. Magennis
中科院分区：
文献类型：
--
作者：
Anita Toulmin;Laura E. Baltierra-Jasso;Michael J. Morten;T. Sabir;P. McGlynn;G. Schröder;Brian O. Smith;S. Magennis
DNA 三路连接 (3WJ) 是分支结构，作为重要的生物中间体和 DNA 纳米结构的组成部分。我们最近推导了完全互补的3WJ的整体结构，并发现它在分支点包含不配对的碱基，这与之前对分支灵活性和分支点反应性的观察结果一致。通过结合高分辨率单分子福斯特共振能量转移、分子建模、时间分辨系综荧光光谱以及完全互补的 3WJ 的首次 19F 核磁共振观察，我们现在表明 3WJ 结构可以根据分支点的序列采用多种不同的构象。具有富含 GC 的分支点的 3WJ 采用开放构象，在分支处具有不配对的碱基，并在分支点处采用至少一种具有增加数量的碱基相互作用的附加构象。这种结构多样性对体内分支相互作用和加工以及技术应用具有影响。
DNA three-way junctions (3WJs) are branched structures that serve as important biological intermediates and as components in DNA nanostructures. We recently derived the global structure of a fully complementary 3WJ and found that it contained unpaired bases at the branchpoint, which is consistent with previous observations of branch flexibility and branchpoint reactivity. By combining high-resolution single-molecule Förster resonance energy transfer, molecular modeling, time-resolved ensemble fluorescence spectroscopy, and the first 19F nuclear magnetic resonance observations of fully complementary 3WJs, we now show that the 3WJ structure can adopt multiple distinct conformations depending upon the sequence at the branchpoint. A 3WJ with a GC-rich branchpoint adopts an open conformation with unpaired bases at the branch and at least one additional conformation with an increased number of base interactions at the branchpoint. This structural diversity has implications for branch interactions and processing in vivo and for technological applications.