Localization estimation of ionizing radiation-induced abasic sites in DNA in the solid state using fluorescence resonance energy transfer

Akamatsu, Ken; Shikazono, Naoya; Saito, Takeshi*

Clustered DNA damage is considered an important factor in determining the biological consequences of ionizing radiation. We here succeeded in estimating the localization of abasic sites (APs) in DNA irradiated with ionizing radiation using fluorescence resonance energy transfer (FRET) without any involvement of repair enzyme functions. A linearized plasmid was irradiated with Co -rays, the He beam, and the C beam in the solid state. A donor or acceptor fluorescent probe with a nucleophilic O-amino group was used to label APs. The results showed that the C beam likely produced close APs within a track. On the other hand, E values of Co -rays and the He beam were less than those of the C beam, increased with increasing AP density, and were slightly greater than those of randomly distributed APs.