发展适合水溶液中氧化鸟嘌呤体系的极化力场

Developing polarizable force field for oxidized guanine in aqueous solution

氧化碱基在生物体内的堆积会造成生物体的衰老、病变甚至引发癌症.近年来,人们大力发展极化力场进行生物体系性质的研究,但还没有应用到氧化DNA体系中.本文针对最常见的氧化鸟嘌呤发展了适用于水溶液中氧化鸟嘌呤体系的极化力场,在原ABEEMσπ浮动电荷力场基础上设定了新的电荷守恒条件,并添加和调整了必要的参数.对气相及水溶液中氧化碱基单体、氧化核苷酸与Na＋的复合物及气相下氧化核苷酸与Na＋和1~10个水的复合物体系进行了电荷计算和动力学模拟.通过对体系电荷及结构的分析证明,新力场适当地考虑了体系的极化效应和电荷转移,并保持了碱基面的平整性,更适合氧化鸟嘌呤体系性质的研究.

The accumulation of oxidized bases in the body can cause the aging of the organism,lesions,even cancer.In recent years,people have developed the polarization force field to research the properties of biological system,but haven＇t applied to oxidized DNA system.This paper developes a polarizable force field for oxidized guanine in aqueous solution,which set a new charge conservation conditions,fitted and adjusted the necessary charge parameters and structure parameters based on the original ABEEMσπfluctuating charge force field.The new force field is applied to calculate the charge of base monomer,the complex system of nucleotide and sodium,and the complex system of nucleotide,sodium and 1~10water.Also this paper penforms the dynamic simulation by using new force field.Through analyzing the charge and structure of the system,the new ABEEMσπfluctuating charge force field has been proved can in view of the polarization effect and the charge transfer suitably and kept the base plane.New ABEEMσπfluctuating charge force field is more suitable for studying the properties of oxidized guanine system.