Damage mechanism of hydroxyl radicals toward adenine–thymine base pair  

作　　者：谈荣日 王东琪 张丰收 

机构地区：[1]College of Communication and Electronics,Jiangxi Science & Technology Normal University [2]The Key Laboratory of Beam Technology and Material Modification of the Ministry of Education,College of Nuclear Science and Technology,Beijing Normal University [3]Guizhou Key Laboratory for Photoelectric and Application,College of Science,Guizhou University [4]Institute of High Energy Physics,Chinese Academy of Sciences [5]Beijing Radiation Center [6]Center of Theoretical Nuclear Physics,National Laboratory of the Heavy Ion Accelerator of Lanzhou

出　　处：《Chinese Physics B》2014年第2期431-436,共6页中国物理B（英文版）

基　　金：Project supported by the National Natural Science Foundation of China (Grant Nos.11025524 and 11161130520);the National Basic Research Program of China (Grant No.2010CB832903);the Natural Science Foundation of Guizhou Province of China (Grant No.J20122141);the Fund in the framework of a Frontier of Novelty Program of the Chinese Academy of Sciences for one of the authors (Wang Dong-Qi) (Grant No.Y1515540U1);the Research Fund for the Doctoral Program of Jiangxi Science and Technology Normal University (Grant No.3000990110)

摘　　要：The adenine-thymine base pair was studied in the presence of hydroxyl radicals in order to probe the hydrogen bond effect. The results show that the hydrogen bonds have little effect on the hydroxylation and dehydrogenation happened at the sites, which are not involved in a hydrogen bond, while at the sites involved in hydrogen bond formation in the base pair, the reaction becomes more difficult, both in view of the free energy barrier and the exothermicity. With a 6-311 ＋＋G（d,p） level of description, both B3LYP and MP2 methods confirm that the C8 site of isolated adenine has the highest possibility to form covalent bond with the hydroxyl radicals, though with different energetics： B3LYP predicts a barrierless pathway, while MP2 finds a transition state with an energy of 106.1 kJ/mol. For the dehydrogenation reactions, B3LYP method predicts that the free energy barrier increases in the order of HN9 〈 HN61 〈 HN62 〈 H2 〈 H8.The adenine-thymine base pair was studied in the presence of hydroxyl radicals in order to probe the hydrogen bond effect. The results show that the hydrogen bonds have little effect on the hydroxylation and dehydrogenation happened at the sites, which are not involved in a hydrogen bond, while at the sites involved in hydrogen bond formation in the base pair, the reaction becomes more difficult, both in view of the free energy barrier and the exothermicity. With a 6-311 ＋＋G（d,p） level of description, both B3LYP and MP2 methods confirm that the C8 site of isolated adenine has the highest possibility to form covalent bond with the hydroxyl radicals, though with different energetics： B3LYP predicts a barrierless pathway, while MP2 finds a transition state with an energy of 106.1 kJ/mol. For the dehydrogenation reactions, B3LYP method predicts that the free energy barrier increases in the order of HN9 〈 HN61 〈 HN62 〈 H2 〈 H8.

关 键 词：DNA damage hydrogen bond effect HYDROXYLATION DEHYDROGENATION 

分 类 号：O571.33[理学—粒子物理与原子核物理] Q523[理学—物理]