DNA STABILITY AND FLEXIBILITY: A THERMODYNAMIC STUDY

DNA 稳定性和灵活性：热力学研究

• 批准号: 3271679
• 负责人: KENNETH J. BRESLAUER
• 金额: $ 12.04万
• 依托单位: RUTGERS, THE STATE UNIV OF N.J.
• 依托单位国家: 美国
• 财政年份: 1979
• 资助国家: 美国
• 起止时间: 1979-04-01 至 1990-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3271679
• 关键词: DNA; chemical stability; circular dichroism; conformation; intermolecular interaction; ionic strengths; microcalorimetry; nuclear magnetic resonance spectroscopy; nucleic acid chemical synthesis; nucleic acid sequence; nucleic acid structure; solutions; thermodynamics; ultraviolet spectrometry

Our goal is to develop a thermodynamic library of the sequence-dependent molecular forces that dictate and control DNA secondary structures in solution. These data will be used to predict the sequence-dependent structural preferences of local domains along the DNA polymer chain. Such a predictive ability will allow us to search for correlations between specific structural features and particular functional roles. The thermodynamic data required to achieve this predictive power will be obtained from calorimetric studies on selected oligomeric and polymeric DNA duplexes. Specifically, relative stabilities (DeltaG), temperature-dependent flexibilities (DeltaH, DeltaCp), and melting cooperativities (DeltaHv.H./DeltaHcal.) will be determined as a function of base sequence for fully-bonded duplexes, hairpins, cruciform-like structures, bulge loops, internal loops, and duplexes containing selectively modified bases. Significantly, calorimetry represents the only experimental method by which the relevant thermodynamic data can be obtained in a direct and model-independent manner. The proposed studies will provide us with complete sequence-dependent thermodynamic profiles for each secondary structural feature. Such data will permit the construction of a phase diagram in which DNA secondary structural preferences are mapped as a function of base sequence and temperature. Considering the potential role of conformational heterogeneity as a mechanism for selective, local control of events such as protein-nucleic acid interactions, drug-DNA binding, gene expression, and DNA packing, an ability to predict local conformational prefernces in DNA polymers is of the utmost importance. The calorimetric experiments described in this proposal represent a continuation of our efforts to obtain the thermodynamic data required to achieve this predictive ability.

我们的目标是开发一个热力学库的序列依赖 决定和控制DNA二级结构的分子力， 溶液 这些数据将用于预测序列依赖性 沿着DNA聚合物链的局部结构域沿着的结构偏好。 等 一种预测能力将使我们能够寻找 具体的结构特征和特定的功能作用。 实现这种预测能力所需的热力学数据将是 从对选定的寡聚和多聚DNA的量热研究中获得 双链体。 具体而言，相对稳定性（DeltaG）， 温度依赖性柔性（Δ H、Δ Cp）和熔融 合作度（Δ Hv.H./Δ Hcal.）将被确定为 完全键合的双链体、发夹、十字形样的碱基序列 结构、凸起环、内环和含有 选择性修饰的碱基。 值得注意的是，量热法是唯一 实验方法，通过该方法可以获得相关的热力学数据。 以直接和独立于模型的方式获得。 拟议的研究将为我们提供完整的序列依赖性 每个二级结构特征的热力学曲线。 这样的数据 将允许构建一个相图，其中DNA二级 结构偏好被映射为碱基序列的函数， 温度 考虑到构象异质性的潜在作用， 选择性局部控制事件的机制，如蛋白质-核酸 酸相互作用，药物-DNA结合，基因表达和DNA包装， 预测DNA聚合物中局部构象偏好的能力是 最重要的。 本文中描述的量热实验 这项建议是我们继续努力争取 热力学数据需要实现这种预测能力。