STRUCTURE AND INTERACTIONS OF DNA

一个主要的目标是更好地了解单分子动力学 散布在螺旋边界之间的DNA多核苷酸链; 了解哪些因素对发展适当的 复制和转录过程中中间体的结构模型， 两个需要DNA的生物过程采用局部结构， 与家族螺旋型不同。 的构象转变 pBR 322 DNA，一个小的，特征良好的标本，适合大规模 制备，将研究和分析高分辨率熔融 技术. 该DNA的热分散曲线将通过以下方法产生： 吸光度差近似法，并进行了几个 热力学分析的形式。 目标是建立一个 pBR 322 DNA的完整和明确的变性图谱，以及一些 片段、重组体、近亲和突变体形式， 确认地图的细节，并量化 统计力学分析 需要这些信息来计算 已知序列DNA中每个残基对在宽范围内的状态 的温度。 直接分析熔解曲线的方法将 还应采取措施，以确定这种方法对DNA的效力， 未知序列，并提供独立的确认值 稳定性和环路参数。 另一个目标集中在如何当地水milleu和 凝聚阳离子的共球影响核酸的稳定性 螺旋 自由能的变化与转移有关， 从一种溶剂热诱导螺旋有序产生无序跃迁 将用一系列不同的螺旋来研究阳离子与另一个阳离子的相互作用 在溶液中一起，以建立对小到 3 cal/mol. bp。 与溶剂同位素有关的自由能变化 对从H2O到D2 O的过渡转移的影响， 还将检测不同的一价阳离子。

A major goal is to better understand the molecular dynamics of the single polynucleotide chain of DNA interspersed between helical boundaries; an understanding of which is essential to the development of suitable structural models for intermediates during replication and transcription, two biological processes that require DNA adopt local structures that differ from the familial helical forms. The conformational transitions of pBR322 DNA, a small, well characterized specimen suited to large scale preparation, will be studied and analyzed by high resolution melting techniques. Thermal dispersion profiles of this DNA will be produced by the absorbance difference-approximation method, and subjected to several forms of thermodynamic analysis. The objective will be to establish a complete and unambiquous denaturation map of pBR322 DNA, and a number of fragments, recombinants, close descendents and mutant forms in order to confirm details of the map and to quantitate the parameters of a statistical mechanical analysis. Such information is needed to calculate the state of each residue pair in DNAs of known sequence over wide ranges of temperature. A direct approach to the analysis of melting curves will also be undertaken to establish the efficacy of such an approach to DNAs of unknown sequence and to provide independent confirmation of values for stability and loop parameters. Another goal focuses on the question of how the local aqueous milleu and cospheres of condensed cations affect the stability of nucleic acid helixes. The change in free energy associated with the transfer of thermally induced helix order yield disorder transitions from one solvent cation to another will be investigated with an array of different helixes together in solution to establish a sensitivity to differences as small as 3 cal/mol.bp. The free energy change associated with the solvent isotope effect upon the transfer of transitions from H2O to D2O containing the different monovalent cations will also be examined.