Human telomere quadruplex: refolding and selection of individual conformers via RNA/DNA chimeric editing.
Human telomere quadruplex: refolding and selection of individual conformers via RNA/DNA chimeric editing.
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DOI：
10.1021/bi602392u
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发表时间：
2007-06
期刊：
影响因子：
2.9
通讯作者：
Jianying Qi;R. Shafer
中科院分区：
文献类型：
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作者：
Jianying Qi;R. Shafer
鸟嘌呤四链体的构象形成的人端粒（HT）重复在含有生理浓度的K+离子的溶液中一直是一个主题，在过去的几年里深入研究。特别感兴趣的是整个折叠图案的方向性，即，平行、反平行或这两种模式的组合，以及顺式和反式之间的糖苷键构象的交替（如果有的话）。另一个问题涉及当存在多于一种物质时解析构象的混合物。我们使用脱氧核糖鸟苷（dG）选择性取代核糖鸟苷（rG）来解决这些问题。使用圆二色性，凝胶电泳，平衡超离心，亚氨基质子NMR的组合，我们能够表明，这些修改可以产生的序列折叠成平行或反平行构象组成的一个或两个链。我们还表明，嵌合编辑的HT序列允许分离的两个构象异构体存在于溶液中的KCl的存在下。用HT设计和控制这里所示的四链体折叠基序的能力可以证明更普遍地用于各种四链体形成序列。
The conformation of the guanine quadruplex formed by the human telomere (HT) repeat in solutions containing physiological concentrations of K+ ions has been a topic of intensive investigation during the past several years. Of particular interest are the directionality of the overall folding pattern, i.e., parallel, antiparallel, or a combination of these two modes, and the alternation, if any, of the glycosidic bond conformation between syn and anti. An additional issue involves resolving mixtures of conformations when more than one species is present. We approach these questions using selective substitution of riboguanosine, rG, for deoxyriboguanosine, dG. Using a combination of circular dichroism, gel electrophoresis, equilibrium ultracentrifugation, and imino proton NMR, we are able to show that these modifications can yield sequences which fold into parallel or antiparallel conformations consisting of one or two strands. We also demonstrate that chimeric editing of the HT sequence permits isolating one of two conformational isomers existing in solution in the presence of KCl. The ability to engineer and control quadruplex folding motifs illustrated here with HT may prove useful more generally for a variety of quadruplex-forming sequences.