摘要
羟基自由基 (·OH)进攻嘌呤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基组水平上对鸟嘌呤 (G)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和C 8位加成机制 .得产物自由基G5OH·、G8OH· ,且G5OH·易与N 11位H脱水得一个更稳定的产物自由基 ,而G8OH·不易发生开环反应 ,得到与实验一致的结论 .
One important reason for DNA damage is the reaction of ·OH free radical with guanine in DNA molecule. Ab initio DFT/B3LYP calculations at 6—31G basis set level were carried out for the possible product radicals of guanine attacked by·OH. According to the calculated results of total energy, atomic spin density and bond length: the radicals formed by OH addition at C 5 or C 8 were theoretically certified. G5OH· was easy to dehydrate with H at N 11 in order to obtain the stable product radical. However, G8OH·was not easy leading to ring opening. These conclusions were consistent with experimental results. The formation of stable radicals leads to DNA damage.
出处
《中国生物化学与分子生物学报》
CAS
CSCD
北大核心
2003年第1期103-106,共4页
Chinese Journal of Biochemistry and Molecular Biology
