STRUCTURE AND INTERACTIONS OF DNA

一个主要目标是更好地理解单个分子的分子动力学 散布在螺旋边界之间的DNA多核苷酸链； 了解哪些内容对于开发合适的 复制和转录过程中中间体的结构模型， 两个需要DNA的生物过程采用了局部结构， 不同于家族性螺旋型。的构象转变 PBR322 DNA，一个小的，特征良好的样本，适合大规模 制备，将通过高分辨率熔融进行研究和分析 技巧。该DNA的热散射谱将由 吸光度差-近似法，并受几种 热力学分析的形式。目标将是建立一个 完整的pBR322 DNA变性图谱，以及一些 片段、重组体、近亲后代和突变形式 确认地图的详细信息，并量化 统计力学分析。这样的信息需要用来计算 已知序列DNA中每个残基对在很大范围内的状态 温度的变化。分析熔化曲线的直接方法将是 还将采取行动，以确定这种方法对DNA的有效性 未知序列，并提供以下值的独立确认 稳定性和环路参数。 另一个目标关注的问题是，当地的含水毫升和 凝聚态阳离子小球对核酸稳定性的影响 螺旋。与原子转移有关的自由能的变化 一种溶剂的热致螺旋有序屈服无序转变 另一种阳离子将通过一组不同的螺旋来研究 共同在解决方案中建立对微小差异的敏感性 3卡/摩尔.基点。与溶剂同位素有关的自由能变化 对从H2O到D2O的转变的影响 不同的单价阳离子也将被检查。

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.