DNA damage by soft X-ray exposure at oxygen K-edge

酸素K吸収端近傍の軟X線照射によるDNA損傷

菅谷 雄基 ; 成田 あゆみ; 藤井 健太郎; 横谷 明徳

Sugaya, Yuki; Narita, Ayumi; Fujii, Kentaro; Yokoya, Akinari

In order to obtain detailed insights into the physicochemical mechanism of DNA damage induction in terms of photoabsorption modes, we have prepared thin DNA films of closed circular plasmid (pUC18) on a cover slip without any additives. Using this film, we have performed preliminary experiments by exposing to soft X-rays with energies around oxygen K-shell ionization threshold. The DNA damage yields of strand breaks and base lesions or AP sites were quantified by biochemical treatments. We confirmed that the DNA film can work as a specimen irradiation. The DNA damage yields induced by excitation of a K-shell electron of oxygen atoms in DNA were significantly greater than those for oxygen K-ionization.