Spectral change of X-ray absorption near edge structure of DNA thin films irradiated with monochromatic soft X-rays

Fujii, Kentaro; Yokoya, Akinari

In this study, we have investigated the spectral of the X-ray absorption near edge structure (XANES) of DNA caused by exposure to monochromatic soft X-rays. We used a calf thymus DNA thin film as a sample and observed nitrogen K-shell and oxygen K-shell XANES spectral changes. The typical monochromatic soft X-ray energies used for the irradiation (395, 408, 528, and 538 eV) were obtained from SPring-8, BL23SU. These energies correspond to just below nitrogen K-shell, just above nitrogen K-shell, just below oxygen K-shell, and just above oxygen K-shell, respectively. The obtained results indicate that carbonyl groups may be produced in the sample. In particular, the production of a propenal group (O=C-C=C) by oxygen ionization is expected. We will discuss the site selective damage induction in DNA using highly monochromatized synchrotron soft X-rays.