MULTINUCLEAR NMR ANALYSIS OF DNA DYNAMICS

合成的寡聚DNA结构将用1H、31 P和13 C- 核磁共振（NMR）来探索DNA动力学的变化 改变氢键结构。 这些分子包括 例如：（i）完全配对的双链体，（ii）环状结构， 改变未配对碱基的位置和性质，以及（iii） 抗肿瘤-DNA药物复合物。 为了实现这些目标，新 介绍了一种低成本的同位素标记方法 用于产生理想地适合于13 C弛豫测量的低聚物。 将在以下基础上获得精细的三维结构： 核Overhauser增强和J相关光谱数据。 核磁共振弛豫的测量将有助于建立自由的 分子围绕这个平均结构的运动。 同位素 标记程序也为三维NMR创建了一个很好的入口 分析与蛋白质或其他配体相互作用的大DNA分子。 从广义上看，实验的目的是揭示 基因调控的细节。 这项工作将加速认识到 三维DNA动力学和结构的关键决定因素 这取决于序列。 它还将探讨可能是 重要的是了解突变的机制和影响， 嵌入抗肿瘤药物。 这些研究也将有助于 更好地理解整体和局部运动的性质， 大分子

Synthetic oligo-DNA structures will be examined with 1H, 31P and 13C- nuclear magnetic resonance (NMR) to explore the variation of DNA dynamics upon changing the hydrogen-bonded structure. The molecules include examples of: (i) perfectly paired duplexes, (ii) a looped structure which varies the location and nature of the unpaired bases, and (iii) an antitumor-DNA drug complex. In order to accomplish these goals, a new isotope-labeling strategy is introduced that promises a low-cost procedure for creating oligomers ideally suited for 13C relaxation measurements. Refined three-dimensional structures will be obtained on the basis of nuclear Overhauser enhancement and J-correlation spectroscopic data. Measurements of NMR relaxation will help to establish the freedom of movement of the molecule about this average structure. The isotope labeling procedure also creates a good entry for three-dimensional NMR analysis of large DNA molecules interacting with proteins or other ligands. In the broad view, the experiments are designed to uncover mechanistic details in genetic regulation. This work will accelerate the recognition of the crucial determinants of three-dimensional DNA dynamics and structure that depend on sequence. It will also explore the interactions that may be important in understanding mechanisms for mutation and the effects of an intercalating antitumor drug. These studies will also contribute to a better understanding of the nature of overall and local motions in macromolecules.