Acta Chimica Sinica ›› 2010, Vol. 68 ›› Issue (16): 1553-1560.     Next Articles

Full Papers

6-烷基鸟嘌呤与DNA碱基间氢键作用的理论研究

林雪飞,孙成科,姚立峰,陈益山,杨思娅   

  1. (曲靖师范学院化学与化工学院 曲靖 655000)
  • 投稿日期:2010-03-01 修回日期:2010-04-18 发布日期:2010-05-31
  • 通讯作者: 杨思娅 E-mail:yangsiyall@163.com
  • 基金资助:

    DNA碱基烷基化与乳腺癌BRCA1基因启动子区甲基化的分子模拟研究

Theoretical Studies of the Hydrogen-bond Interactions between O6-Alkylguanine and DNA Bases

LIN Xue-Fei, SUN Cheng-Ke, YAO Li-Feng, CHEN Yi-Shan, YANG Si-Ya   

  1. (School of Chemistry & Chemical Engineering, Qujing Normal University, Qujing 655000)
  • Received:2010-03-01 Revised:2010-04-18 Published:2010-05-31

The geometries of hydrogen-bond dimers between DNA bases (adenine, thymine, guanine and cytosine) and guanine, cis-O6-alkylguanine and trans-O6-alkylguanine have been optimized at the B3LYP/6-311+G** level. The complete basis-set extrapolation method was employed at the MP2/ cc-pVXZ(X=D,T)//B3LYP/6-311+G** levels in order to obtain more accurate interaction energies. Counterpoise correction (CP) scheme was also used to take into account of basis set superposition error (BSSE). The all-electron wave functions of these dimers were calculated at the B3LYP/6-311+G** level and the weak interactions were analyzed by atoms in molecules (AIM) method. The calculation results show that the alkylation of O6-guanine can lead to changes of hydrogen-bond interactions between DNA base-pairs, which results in propeller torsions and various displacements between two bases. Furthermore, the obvious decreases in interaction energies and electron densities of base-pair can also be attributed to the alkylation of guanine. Evidently, the alkylation of O6-guanine destabilizes the hydrogen-bond interactions of DNA base-pairs, and the destabilization effect decreases in the order of GC>GG>GA≈GT. Our calculation results are basically in agreement with the experiments.

Key words: guanine, alkylation, DNA bases, hydrogen-bond, atom in molecule (AIM)