Surface plasmon resonance imaging of the conversion of clustered DNA lesions into double strand breaks by Fpg protein

Ionizing radiations induce clustered damage sites known to be severely challenging for the cell's repair machinery. In the present study, we have grafted on a biochip four synthetic oligonucleotide duplexes containing either a single 8-oxoguanine, a single 2'-deoxyribose abasic site or two different clustered damages containing these two lesions on opposite strands. Using a SPR imaging-based DNA array, we qualitatively observed the hierarchy of lesion processing by the base excision repair (BER) enzyme Fpg (Formamidopyrimidine (fapy)-DNA glycosylase). We could notably show that Fpg can convert a cluster of lesions into a potentially lethal double strand break (DSB) and demonstrate that SPR imaging is suitable to investigate the incision steps occurring during the repair process