NaCl及PEG溶液中DNA的变性行为  

Denaturation Behavior of DNA in NaCl and PEG Solutions

作　　者：孙迪[1] 赵双良[1] 尚亚卓[1] 彭昌军[1] 刘洪来[1] 

机构地区：[1]华东理工大学化学工程联合国家重点实验室,化学系,上海200237

出　　处：《华东理工大学学报（自然科学版）》2013年第2期147-150,共4页Journal of East China University of Science and Technology

基　　金：国家自然科学基金(21173079,21136004);中央高校基本科研业务费专项资金

摘　　要：采用紫外光谱法研究了无机盐(NaCl)和聚乙二醇(PEG)存在下的拥挤环境对鲑鱼精子DNA变性行为的影响,并利用相关的模型进行计算对比。研究结果表明,盐的加入影响了DNA分子间静电斥力及碱基对间氢键作用,进而影响DNA的变性温度。PEG的拥挤效应及其与DNA的结合效应竞争的结果导致PEG溶液中DNA的变性温度低于单一水溶液中DNA的变性温度,且随着PEG分子量的增加其降低幅度加大。用密度泛函理论对DNA的变性行为进行了理论研究,利用建立的体相DNA变性的反应分子热力学模型,通过自由能极小原理计算DNA变性温度、变性曲线等,获得NaCl和PEG存在下DNA的变性行为,并与实验结果进行对比,理论计算与实验结果吻合良好。It is of significant importance for DNA research that the effects of salt NaCl and polymer PEG on the denaturation behavior of salmon DNA were studied by UV measurements and relevant model to compare. The results show that the addition of salt has influences on both the electrostatic repulsions between DNA molecules and the hydrogen-bonding of the base pairs, thus affecting the DNA melting temperature. The DNA melting temperature in the presence of PEG is lower than that in the pure DNA aqueous solution, owing to the competition between the crowding effect caused by PEG and the binding of PEG with DNA. The effect of PEG on DNA melting temperature becomes stronger with increasing PEG molecular mass. The density functional theory is applied to study DNA denaturation theoretically. The reaction thermodynamic theory is made to examine the features of bulk denaturation and the denature temperature and denature curve are calculated by the minimum free energy principle. The results can precisely predict the denaturation behavior in NaCl and PEG solutions. The melting temperature is calculated by the established molecular thermodynamic model and the calculated melting temperature matches fairly well with the experimental results.

关 键 词：DNA 变性温度 密度泛函理论 分子热力学模型 

分 类 号：O642[理学—物理化学]