DNA base lesions induced by phorosphorus K-ionization and its Auger decay

Yokoya, Akinari; Usami, Noriko*; Maeda, Munetoshi*

In previous studies, DNA double strand breaks (DSBs) induced by phosphorus K-shell ionization are studied in terms of its cell killing effect. Recently non-DSB type complex damage has been known to induce radiobiological effect such as mutation. The complex damage consists of several base lesions produced in a few nm of DNA molecule, and retard the enzymatic repair process. However there was very little knowledge about the base lesions induced by phosphorus K-shell ionization. In this study, experimental evidences of the production of the base lesions are reported using plasmid DNA as a model molecule. The yields of the base lesions were quantified using base excision repair proteins as enzymatic probes (glycosylases). Several irradiation conditions were tested and the obtained results are compared to discuss the process of the base lesions formation.