Spectroscopy of X-ray absorption fine structure of DNA damage induced by soft X-rays

Fujii, Kentaro; Yokoya, Akinari

We have investigated the change of the spectra of the X-ray absorption near edge structure (XANES) of DNA exposed to monochromatic soft X-rays. We used calf thymus DNA thin films as samples and observed N K-shell and O K-shell XANES spectral changes. The typical monochromatic soft X-ray energies used for the irradiation (380, 435, 560, and 760 eV) were obtained from SPring-8, BL23SU. The observed spectra show the deprotonation from nucleobase and the decomposition of sugar site of the DNA by irradiation. By comparing the spectral changes in XANES with the yields of base lesions and strand breaks, we will discuss the molecular structure of DNA lesions by soft X-irradiation.