Selective damage induction of DNA induced by monochromatic soft X-rays

Fujii, Kentaro

We have revealed that the yields of base lesions as well as strand breaks strongly depend on soft X-ray energy around carbon, nitrogen and oxygen K-edge regions. The K-shell ionization of oxygen most likely contributes to the induction of nucleobase lesions. DNA single strand breaks, on the other hand, are preferably produced just below N K-edge. To investigate the mechanism of molecular changes in DNA irradiated with soft X-rays, we have also measured the spectra of X-ray absorption near edge structure (XANES) of DNA caused by exposure to monochromatic soft X-rays. The obtained results may provide important implications for selective induction of specific types of DNA damage through tuning the energy of soft X-rays.