X-RAY DIFFRACTION STUDIES OF NUCLEIC ACID STRUCTURES

核酸结构的 X 射线衍射研究

• 批准号: 2022286
• 负责人: ANDREW H WANG
• 金额: $ 21.28万
• 依托单位: UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN
• 依托单位国家: 美国
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-12-01 至 1998-07-19
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2022286
• 关键词: DNA; DNA binding protein; RNA; X ray crystallography; Z DNA; chemical stability; circular DNA; conformation; crystallization; high performance liquid chromatography; ligands; metal complex; nuclear magnetic resonance spectroscopy; nucleic acid hybridization; nucleic acid structure; nucleotide analog; oligonucleotides; structural biology; synthetic nucleic acid

The overall objective of this project is to continue investigating the conformational diversities of nucleic acids using x-ray crystallography and nuclear magnetic resonance spectroscopy. Other biophysical techniques, such as laser Raman and circular dichroism spectroscopic methods, will be applied when necessary. Several molecular systems, containing carefully-designed DNA/RNA oligonucleotide sequences associated with important biological implications, will be studied and their structures correlated with biological functions. We propose to study the following DNA/RNA systems for various objectives. (i). Unusual nucleic acid con formations: Several new unusual nucleic acid conformations (e.g., Z-DNA, H-DNA, I-DNA, Hoogsteen helix, telomere, centromere) have been uncovered recently. We will continue to study the molecular basis of those structures and to explore new and unusual conformations. (ii). Nucleic acid structure with defects. Oligonucleotides with different kinds of irregular features such as mismatch, bulge and carcinogen-modified base (e.g., m6G/m4T, benzopyrene-adduct) will be studied. Different modified nucleotide analogs will be incorporated into double helix to assess the effect of them on the stability of various alternative DNA/RNA conformations. (iii). Higher-ordered structures. Nucleic acid molecules can form quite complex tertiary structures like triple helix, hairpin, cruciform, pseudoknot and circular molecules, all of which are important in biological processes (e.g., in gene regulation and recombination). We will continue to focus on the structures of hairpins and circular DNA. (iv). Ligand-nucleic acid interactions. The function of nucleic acids depends on their interactions with other molecules. We will study the interactions between a number of small ligands (in particular metal ions) and nucleic acids by x-ray crystallography. We will explore the crystallization of a few non-sequence-specific DNA binding proteins (e.g., M13 gene V protein and HU) and their DNA complexes. A significant number of those molecules described above are already in various stages of structural analysis. New molecules in the above scope will be synthesized and studied structurally by x-ray diffraction and NMR. The detailed descriptions of various molecular systems are listed in the Preliminary Results section. Our studies will help understand the molecular forces that governs the structure, dynamics and energetics of nucleic acids.

该项目的总体目标是继续调查 使用 X 射线晶体学分析核酸的构象多样性 和核磁共振波谱。其他生物物理学 技术，例如激光拉曼和圆二色光谱 方法，必要时会采用。几个分子系统， 含有精心设计的 DNA/RNA 寡核苷酸序列 与重要的生物学意义相关，将被研究和 它们的结构与生物功能相关。我们建议 出于各种目的研究以下 DNA/RNA 系统。 （我）。不寻常的核酸构象：几种新的不寻常核酸 酸性构象（例如，Z-DNA、H-DNA、I-DNA、Hoogsteen 螺旋、端粒、 着丝粒）最近被发现。我们将继续研究 这些结构的分子基础并探索新的和不寻常的 构象。 (二).核酸结构有缺陷。 寡核苷酸与 不同种类的不规则特征，例如不匹配、凸起和 致癌物修饰碱基（例如 m6G/m4T、苯并芘加合物）将 研究过。不同的修饰核苷酸类似物将被掺入 双螺旋来评估它们对各种稳定性的影响 替代 DNA/RNA 构象。 （三）。高阶结构。核酸分子可以形成相当 复杂的三级结构，如三螺旋、发夹、十字形， 假结和环状分子，所有这些在 生物过程（例如基因调控和重组）。我们 将继续关注发夹和环状DNA的结构。 （四）。配体-核酸相互作用。核酸的功能 取决于它们与其他分子的相互作用。我们将研究 许多小配体（特别是金属离子）之间的相互作用 和核酸通过X射线晶体学。我们将探索 一些非序列特异性 DNA 结合蛋白的结晶 （例如，M13 基因 V 蛋白和 HU）及其 DNA 复合物。 上述大量分子已经存在于 结构分析的各个阶段。上述范围内的新分子 将通过X射线衍射进行合成和结构研究 核磁共振。列出了各种分子系统的详细描述 在初步结果部分。我们的研究将有助于理解 控制结构、动力学和能量的分子力 核酸。