Decondensation behavior of DNA chains induced by multivalent cations at high salt concentrations:Molecular dynamics simulations and experiments

作     者：蒋杨伟 冉诗勇 何林李 王向红 章林溪 Jiang Yang-Wei;Ran Shi-Yong;He Lin-Li;Wang Xiang-Hong;Zhang Lin-Xi

作者机构：Department of Physics Zhejiang University Department of Physics Wenzhou University Department of Electrical and Electronic Engineering Wenzhou Vocational and Technical College 

出 版 物：《Chinese Physics B》 (中国物理B（英文版）)

年 卷 期：2015年第24卷第11期

页      面：610-618页

核心收录：

学科分类：0710[理学-生物学] 071010[理学-生物化学与分子生物学] 081704[工学-应用化学] 07[理学] 08[工学] 0817[工学-化学工程与技术] 0805[工学-材料科学与工程（可授工学、理学学位）] 0704[理学-天文学] 

基　　金：supported by the National Natural Science Foundation of China(Grant No.31340026) the Natural Science Foundation of Zhejiang Province,China(Grant Nos.Z13F20019 and LQ12E01003) the Science and Technology Project of Zhejiang Science and Technology Department,China(Grant No.2014C31147) 

主　　题：DNA decondensation salt concentration multivalent cations molecular dynamics simulation 

摘      要：Using molecular dynamics simulations and atomic force microscopy （AFM）, we study the decondensation process of DNA chains induced by multivalent cations at high salt concentrations in the presence of short cationic chains in solutions. The typical simulation conformations of DNA chains with varying salt concentrations for multivalent cations imply that the concentration of salt cations and the valence of multivalent cations have a strong influence on the process of DNA decondensation. The DNA chains are condensed in the absence of salt or at low salt concentrations, and the compacted conformations of DNA chains become loose when a number of cations and anions are added into the solution. It is explicitly demonstrated that cations can overcompensate the bare charge of the DNA chains and weaken the attraction interactions between the DNA chains and short cationic chains at high salt concentrations. The condensation-decondensation transi- tions of DNA are also experimentally observed in mixing spermidine with X-phage DNA at different concentrations of NaCl/MgCl2 solutions.