First-principles calculations of molecular structure and electronic state changes in DNA induced by radiation-induced holes

Sekikawa, Takuya; Hwang, B.*; Ishizaka, Masato*; Matsuya, Yusuke*  ; Kawai, Hiroyuki*; Ono, Yoshiaki*; Sato, Tatsuhiko   ; Kai, Takeshi   

Deoxyribonucleic acid (DNA) carries the genetic information of living organisms through various combinations of guanine, cytosine, adenine, and thymine, and radiation biological effects are mainly caused by damage to DNA. In this study, in order to theoretically investigate the transient molecular conformational changes that occur before DNA damage takes hold, we analyzed the behavior of the sites responsible for the conformational changes and chemical reactions by targeting the DNA that produced the holes using the first-principles calculation software OpenMX. As a result, it was confirmed that the holes reproduce the event of trapping in the guanine molecule of DNA, which reproduces the experimental results, and it was also newly found that the DNA sugar chain shows intense molecular fluctuation. The results of this study are expected to contribute to the elucidation of the first-phase process of radiation biological effects.