STRUCTURAL INVESTIGATION OF DNA QUADRUPLEXES BY NMR

通过 NMR 对 DNA 四链体进行结构研究

• 批准号: 6119288
• 负责人: YOKO S HAGA
• 金额: $ 0.54万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-07-01 至 2000-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6119288
• 关键词: biological products; biomedical resource; nucleic acids

The goal of my PhD thesis project was to obtain information about the biophysical characteristics of a potentially biologically significant higher-order DNA structural motif. We have been interested in structures of DNA quadruplexes whose core architecture is based on guanine quartets (G-quartets). It has been suggested that G-quartet structures may form at the natural eukaryotic chromosome ends (telomeres) and contribute to protein binding, regulation, or resistance to degradation. Telomeres are usually composed of simple tandem repeats of guanine-rich sequences associated with telomeric binding proteins. Telomeric sequences are typically found to be highly conserved across phylogenetically diverse organisms. More recently, however, many budding yeast telomeres have been shown to have more divergent sequences both in length and in base composition. Oligonucleotides having one to two repeats of the yeast telomeric sequences are usually less stable thermodynamically compared to those with more conserved sequences, such as ones from ciliate protozoa. My thesis project involved the characterization of several quadruplex-forming guanine-rich oligonucleotides from budding yeast telomeric and related sequences. Solution nuclear magnetic resonance (NMR) and other spectroscopic methods were used to understand their physical chemical features, the factors contributing to the stability of the complexes, and to determine high resolution solution structures of those oligonucleotides. The recent improvement of our NMR spectrum analysis tool, Sparky, has been very useful for our structural determination process. The capability of the program to visualize structural models and inter-proton distances using MidasPlus within Sparky accelerated tis process enormously. The incorporation of graphical tools to the structural determination process, spectrum analysis (Sparky), distance calculation (MARDIGRAS), structure elucidation (Amber, X-PLOR) was exciting and it has already helped the iterative nature of this process.

我的博士论文项目的目标是获取有关 潜在生物学特性的生物物理特征 显着的高阶 DNA 结构基序。 我们曾经 对 DNA 四链体的结构感兴趣，其核心架构 基于鸟嘌呤四重奏（G-四重奏）。 有人建议 G四联体结构可能在天然真核染色体上形成 末端（端粒）并有助于蛋白质结合、调节或 抗降解性。 端粒通常由简单的 与端粒相关的富含鸟嘌呤序列的串联重复 结合蛋白。 端粒序列通常被发现是 在系统发育多样化的生物体中高度保守。 更多的 然而，最近，许多出芽酵母端粒已被证明 在长度和碱基组成上都有更多不同的序列。 具有一到两个酵母端粒重复的寡核苷酸 与那些序列相比，序列通常在热力学上不太稳定 具有更保守的序列，例如来自纤毛虫原生动物的序列。 我的 论文项目涉及几个特征 来自芽殖酵母的形成四链体的富含鸟嘌呤的寡核苷酸 端粒和相关序列。 溶液核磁共振 （核磁共振）和其他光谱方法被用来了解它们 物理化学特性、影响稳定性的因素 配合物的分析，并确定高分辨率溶液结构 这些寡核苷酸。 我们核磁共振谱图的最新改进 分析工具 Sparky 对我们的结构非常有用 确定过程。 程序可视化的能力 使用 MidasPlus 内的结构模型和质子间距离 Sparky 极大地加速了这一过程。 纳入 结构测定过程、光谱的图形工具 分析（Sparky）、距离计算（MARDIGRAS）、结构 阐明（Amber、X-PLOR）令人兴奋，它已经帮助了 这个过程的迭代性质。