Effect of the DNA Polarity on the Relaxation of Its Electronic Excited States

• DOI: 10.1021/acs.jpclett.3c02580
• Publication Date: 2023-11-06T20:56:15Z
• Authors: Vasilis Petropoulos; Lorenzo Uboldi; Margherita Maiuri; Giulio Cerullo; Lara Martinez-Fer...; Evangelos Balanikas; Dimitra Markovitsi
• Keywords: Nucleobase; Phosphodiester bond; Potential energy surface

The DNA polarity, i.e., the order in which nucleobases are connected together via phosphodiester backbone, is crucial for several biological processes. But, so far, there has not been experimental evidence regarding its effect on relaxation of electronic excited states. Here we examine this aspect two dinucleotides containing adenine and guanine: 5′-dApdG-3′ 5′-dGpdA-3′ water. We used different femtosecond transient absorption setups: one providing high temporal resolution broad spectral coverage (330–650 nm) between 30 fs 50 ps, other recording decays at selected wavelengths until 1.2 ns. spectra corresponding to minima potential energy surface first state were computed by quantum chemistry methods. Our results show that charge transfer formed with a ∼75% higher yield exhibits slower decay (170 ± 10 ps vs 112 12 ps) compared 5′-dApdG-3′.