Acta Chimica Sinica ›› 2011, Vol. 69 ›› Issue (23): 2787-2795.DOI: 10.6023/A1106172 Previous Articles     Next Articles

Full Papers


林雪飞,孙成科,杨思娅*, 余仕问, 姚立峰, 陈益山   

  1. (曲靖师范学院化学化工学院 曲靖 655000)
  • 投稿日期:2011-06-17 修回日期:2011-10-20 发布日期:2011-11-01
  • 通讯作者: 杨思娅
  • 基金资助:


Theoretical Studies of the Abnormal Hydrogen-bond Interactions between O6-Methylguanine and O4-Methylthymine and DNA Bases

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

  1. (School of Chemistry & Chemical Engineering, Qujing Normal University, Yunnan 655000)
  • Received:2011-06-17 Revised:2011-10-20 Published:2011-11-01

The geometries of abnormal Watson-Crick hydrogen-bond dimers between cis/trans- O6-methylguanine and cis/trans-O4-methylthymine and DNA bases (adenine, thymine, cytosine and guanine) 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) theory. The calculation results show that the methylation of O6-guanine and O4-thymine can lead to changes of hydrogen-bond interactions between DNA base-pairs, which results in propeller torsions and various displacements between base pairs. The obvious decreases in interaction energies and electron densities between base-pairs is attributed to the methylation on O6-guanine and O4-thymine. Furthermore, the methylation of O6-guanine and O4-thymine destabilize the hydrogen-bond interactions of DNA base-pairs, and compared with anti conformations, the destabilization effect of the methylation on cis DNA base-pairs is more evident. Our calculation results are basically in agreement with the experiments.

Key words: methylation, DNA base, hydrogen-bond, AIM, topology analysis