OPTICAL PROPERTIES OF NUCLEIC ACID CONSTITUENTS

核酸成分的光学性质

• 批准号: 3295106
• 负责人: LEIGH B CLARK
• 金额: $ 7.67万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 1987
• 资助国家: 美国
• 起止时间: 1987-07-01 至 1990-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3295106
• 关键词: adenine; benzimidazoles; chromophore; circular dichroism; conformation; dichroism; dipole moment; electronic spectra; hydrogen bond; molecular stacking; nucleic acid structure; nucleobase; phosphates; polarimetry; polynucleotides; purines; pyrimidines; ribose; solutions; spectrometry; thymine; ultraviolet spectrometry

The proposed work is aimed at developing and refining methods used to obtain nucleic acid conformations in solution from optical measurements. Such information and the corresponding models it produces are prerequisite for understanding the dynamics and biological mechanisms of nucleic acids. The most powerful and widely used optical methods for sensing detailed solution state conformations are circular dichroism and linear dichroism spectroscopies, however both require specific optical information regarding the electric dipole transition moments of the purine and pyrimidine monomeric chromophores. Much of these essential data have never been available, and this lack of monomer data has undermined the interpretation of the optical properties of polynucleotides. The overall aim of the proposed research is to provide all necessary missing information. It is therefore proposed to obtain absorption curves extending well into the vacuum UV region for radiation polarized along various axes of purine and pyrimidine single crystals. The absorption curves will be obtained from experimental polarized reflection spectra through Kramers- Kronig analysis. Exciton coupling will be treated with an iterative procedure in an effort to account for crystal intermolecular interaction effects and to extract free molecule properties for the crystal spectra. The adenine and thymine chromophores are the least well studied, so that crystals containing these systems will form the bulk of the initial effort. In addition to determining the principal polarization direction of each transition we hope whenever possible to obtain the other components of the absorptivity tensor. Sequences of crystals involving base, nucleoside, nucleotide and ionic forms (if available) will be studied in order to answer long-standing questions about the effect of ribose and phosphate substitution and protonation on the base chromophore. Hydrogen bonded A:T and G:C complexes will be examined to verify and study the striking conclusions drawn from the only previous study of such complexes. We plan to grow and examine dinucleoside phosphate single crystals in order to study the effects of stacking interactions and to refine the protocols for calculating the optical properties of the polynucleotide in general. Longer oligonucleotide systems will also be sought for study.

拟议的工作旨在开发和完善方法 用于从光学获得溶液中的核酸构象 测量。 这些信息以及对应的型号吧 产生是了解动态的先决条件 核酸的生物学机制。 最强大和 广泛使用的光学方法来感知详细的解决方案状态 构象有圆二色性和线性二色性 光谱学，但是两者都需要特定的光学信息 关于嘌呤的电偶极跃迁矩和 嘧啶单体发色团。 其中许多都是必不可少的 数据从未可用，并且单体数据的缺乏已经 破坏了对光学特性的解释 多核苷酸。 拟议研究的总体目标是 提供所有必要的缺失信息。因此建议 获得延伸至真空紫外的吸收曲线 沿着嘌呤和不同轴偏振的辐射区域 嘧啶单晶。 将获得吸收曲线 来自克莱默斯的实验偏振反射光谱- 克罗尼格分析。 激子耦合将用 迭代过程以努力解释晶体 分子间相互作用效应并提取游离分子 晶体光谱的性质。 腺嘌呤和胸腺嘧啶 发色团研究得最少，因此晶体 包含这些系统将构成初始工作的大部分。 除了确定主偏振方向 每一次转变我们都希望尽可能获得另一次转变 吸收率张量的分量。 晶体序列 涉及碱基、核苷、核苷酸和离子形式（如果 可用）将进行研究，以回答长期存在的问题 关于核糖和磷酸盐取代的影响的问题 和基础发色团上的质子化。 氢键 A:T 和 G:C 复合物将被检查以验证和研究 从之前对此类研究的唯一研究中得出的惊人结论 复合物。 我们计划种植和检查磷酸二核苷 单晶以研究堆叠的影响 相互作用并完善计算光学的协议 多核苷酸的一般特性。 更长 寡核苷酸系统也将被寻求研究。