Molecular dynamics of DNA strand breaks induced by tritium transmutation

2016 Fiscal Year Final Research Report

• Project/Area Number: 15K13614
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Physical chemistry
• Research Institution: Tohoku University
• Principal Investigator: Kono Hirohiko 東北大学, 理学研究科, 教授 (70178226)
• Co-Investigator(Renkei-kenkyūsha): AKIYAMA Kimio 東北大学, 多元物質科学研究所, 准教授 (10167851) ; SEKINE Tsutomu 東北大学, 高度教養教育・学生支援機構, 教授 (20154651) ; KANNO Manabu 東北大学, 大学院理学研究科, 助教 (30598090)
• Project Period (FY): 2015-04-01 – 2017-03-31
• Keywords: 密度汎関数強束縛法 / 反応動力学 / 原子分割エネルギー / DNA鎖切断 / 塩基脱離 / ヒドロキシルラジカル / 水素引き抜き / トリチウム壊変

Outline of Final Research Achievements

We simulated DNA strand breaks induced through β decays of tritium atoms contained in a DNA by using the density-functional based tight-binding method for electronic structure　calculations. The results of simulations were analyzed from the aspect of energy and charge transfer to examine the　mechanisms of elementary processes in DNA strand breaks. Charge rearrangement occurs after β decays of tritium, which results in a neutral radical species. We found that after a β decay of a tritium atom bound to the 3' or 5'-carbon in a sugar, a P-O bond of an adjacent phosphate group breaks. This reaction is mediated through energy and charge transfer between the neighboring sugar and phosphate and terminates with a single strand break; a double strand break, difficult to repair, never takes place as long as two tritium atoms happen to be absorbed to two sugars bridged by the same base pair.

Free Research Field

理論化学