A Novel DNA Hairpin Substrate for Bleomycin

A 16-nucleotide DNA hairpin containing 4-aminobenzo[g]quinazoline-2-one 2′-deoxyribose at position 15 has been prepared and found to lack significant fluorescence. When treated with Fe(II)·BLM, the hairpin was found to undergo oxidative transformation selectively at position 15. The predominant fluorescent product was characterized and quantified. The pro-fluorescent DNA hairpin was used as a substrate for 15 bleomycin congeners, and the results were compared with those obtained following cleavage of a radiolabeled DNA duplex and PAGE analysis.