介电环境及PH值对DNA构象变化影响的单分子研究

项目名称： 介电环境及PH值对DNA构象变化影响的单分子研究

项目编号： No.11304232

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 数理科学和化学

项目作者： 王艳伟

作者单位： 温州大学

项目金额： 25万元

中文摘要： 研究环境对DNA构象变化的影响对于理解生命现象的基本过程（如DNA复制，压缩和包装等）和开发基因治疗载体技术有基础性的作用。DNA在表面电荷大部分被平衡离子中和后就会发生凝聚，这种同性电荷的吸引现象无法用基于平均场理论的泊松-玻尔兹曼方程解释，通常认为与离子关联效应、介电环境，PH值等因素有关，但具体的凝聚机制还尚未完全理解。本课题以单分子技术为主要手段研究溶剂介电环境及PH值对DNA构型变化的影响，以进一步搞清DNA凝聚与解凝聚的物理机制。实验中利用单分子磁镊，原子力显微镜和动态光散射技术针对不同种类DNA及凝聚剂，通过改变溶剂介电常数（加入酒精、氨基羧酸等）及PH值测量DNA凝聚及解凝聚过程中的单分子力谱和形态变化；同时对DNA的弛豫动力学性质、凝聚力及DNA长度和持久长度变化等进行分析。根据实验数据，结合溶液中静电作用理论，分析它们在DNA凝聚与解凝聚构象变化中的作用机制与规律。

中文关键词： DNA 凝聚；电荷逆转；介电常数；ph值；单分子技术

英文摘要： To study the influence of environment on DNA conformation changes plays fundamental role on understanding the basic process of life phenomenon (such as DNA replication, compression and packing, etc.) and developing of gene therapy vectors technology. DNA condensation will occur when the surface charges are neutralized mostly by counterions. This kind of like-charge attraction can't interpret using Poisson - Boltzmann equation which based on mean field theory. Existing research results show that this process is linked to ion correction effect, dielectric environment, and PH value et al, but the specific condensation kinetics mechanism is not clearly.This topic use single molecular technology as the main means to study the influence of solvent dielectric environment and PH value on DNA configuration changes, in order to further understand the physical mechanism of DNA condensation and decondensation in solution.We use the single molecular magnetic tweezers, atomic force microscopy and dynamic light scattering technology to study the influence of solvent dielectric environment and PH value on DNA conformational change.According to different types of DNA and compensating agent, we measured single molecule spectrum and morphological changes in the process of DNA condensation and decondensation by changing the solvent

英文关键词： DNA condensation；charge inversion；dielectric constant；PH value；single molecule techique