The synthesis for the phosphoramidite of 8-oxoG,[19 (link)] 8-oxoA,[31 (link)] and 8-oxoI/8-BrI[32 (link)] were previously reported by us and the same methodology was used to prepare all oligonucleotides, via solid-phase synthesis. The synthesis of oligonucleotides of RNA containing 8-BrA was not possible in our hands due to its transformation to the corresponding 8-methylamine derivative (upon AMA-deprotection of the synthesized oligonucleotide, Figure S-4). It is possible that oligonucleotides containing this modified nucleoside can be attained by varying the deprotection conditions, however we have not been yet successful. UV-vis spectroscopy of all small molecules was carried out on a Perkin Elmer λ−650 UV/vis spectrometer using quartz cuvettes (1 cm pathlength). All experiments described herein were carried out in triplicate.