摘要
羟基自由基(·OH)进攻嘧啶碱基是破坏核酸造成DNA断链损伤的重要原因之一.采用密度泛函(DFT)理论中B3LYP方法在6—31G基组水平上对胸腺嘧啶(thymine,简写为"T")受羟基自由基进攻形成的各种可能产物自由基进行几何全优化.根据总能量、键长和自旋密度的计算结果,从理论上确认了C_5位加成机制.得稳定产物自由基T5OH·,且T5OH·不易脱水与N_3位H脱水得一个更稳定的产物自由基.该稳定自由基的形成造成DNA断链损.
It is one of important reasons for the reaction of ·OH with thymine to destroy nucleic acid and damaged DNA. Ab initio DFT/B3LYP calculations at 6-31G basis set level were carried out for the possible product radicals of attacked thymine by ·OH. According to the calculated results of total energy, atomic spin density and bond length, the stable product radical formed by ·OH addition at C_5 was theoretically certified. T5OH· was not easy to dehydrate. The formation of stable radicals leads to damage DNA.
出处
《中央民族大学学报(自然科学版)》
2004年第1期81-85,共5页
Journal of Minzu University of China(Natural Sciences Edition)