Nucleic Acids Research Laboratory, Department of Chemistry, University of Delhi (North Campus), Delhi, India.
Department of Chemistry, Rajdhani College, University of Delhi, New Delhi, India.
J Biomol Struct Dyn. 2021 Jun;39(9):3324-3335. doi: 10.1080/07391102.2020.1764390. Epub 2020 May 19.
Eukaryotic genomes contain a large number of pyrimidine-purine rich regions and such regions can assume varied DNA conformations, including triple-stranded structures. These structures have fascinated scientists because of their considerable therapeutic applications. These structures have also profound implications in the field of nanotechnology as they can be used to develop DNA-based nanostructures and materials. Therefore, for any application, it is important to understand the formation of triplex structures, both in quantitative and qualitative terms. A combination of gel electrophoresis, UV-thermal denaturation and circular dichroism (CD) spectroscopy was used to investigate the formation of inter- as well as intramolecular triplex, in pyrimidine motif at gene of human (HH4) genome. This gene codes for inner tegument protein, which plays crucial roles in viral replication. The said oligopurine•oligopyrimidine duplex was targeted via a designed triple helix forming oligopyrimidine nucleotide (TFO) in intermolecular as well as intramolecular fashion. Our studies revealed that intramolecular triplex formation takes place at acidic as well as at neutral pH; whereas low pH is required for its intermolecular version. This comparative study between inter- and intramolecular triplex allowed us to demonstrate that intramolecular structure is more stable to its intermolecular counterpart. Numerous models for mono-, bi- and trimolecular structures adopted by these DNA sequences have been suggested. This report adds to our existing knowledge about DNA triple helical structures.
真核基因组含有大量嘧啶-嘌呤丰富区域，这些区域可以呈现出多种 DNA 构象，包括三链结构。这些结构引起了科学家的极大兴趣，因为它们具有相当大的治疗应用价值。这些结构在纳米技术领域也有深远的意义，因为它们可以用来开发基于 DNA 的纳米结构和材料。因此，对于任何应用，重要的是要从定量和定性两个方面了解三链结构的形成。本研究采用凝胶电泳、UV-热变性和圆二色性（CD）光谱相结合的方法，研究了人（HH4）基因组嘧啶基序基因中双链体之间和双链体内部的三聚体的形成。该基因编码内衣壳蛋白，在病毒复制中起着至关重要的作用。通过设计的三链形成寡嘧啶核苷酸（TFO），以分子间和分子内的方式靶向寡聚嘧啶-寡聚嘧啶二核苷酸。我们的研究表明，分子内三聚体的形成发生在酸性和中性 pH 值下；而其分子间形式则需要较低的 pH 值。这种分子内和分子间三聚体的比较研究使我们能够证明分子内结构比其分子间结构更稳定。这些 DNA 序列的单、双和三聚体结构已经提出了许多模型。本报告增加了我们对 DNA 三螺旋结构的现有知识。
