Understanding the factors controlling the photo-oxidation of natural DNA by enantiomerically pure intercalating ruthenium polypyridyl complexes through TA/TRIR studies with polydeoxynucleotides and mixed sequence oligodeoxynucleotides
Páraic M. Keane, Kyra O’Sullivan, Fergus E. Poynton, Bjørn La Cour Poulsen, Igor V. Sazanovich, Michael Towrie, Christine J. Cardin, Xue‐Zhong Sun, Michael W. George, Thorfinnur Gunnlaugsson, Susan J. Quinn, John M. Kelly
Abstract
515 nm in the TrA for the reduced ruthenium complex. It is found that efficient electron transfer requires that the complex be intercalated at a G-C base-pair containing site. Significantly, changes in the nucleobase vibrations of the TRIR spectra induced by the bound excited state before electron transfer takes place are used to identify preferred intercalation sites in mixed-sequence oligodeoxynucleotides and natural DNA. Interestingly, with natural DNA, while it is found that quenching is inefficient in the picosecond range, a slower electron transfer process occurs, which is not found with the mixed-sequence duplex-forming oligodeoxynucleotides studied.