Photoinduced electron transfer in 5-bromouracil labeled DNA. A contrathermodynamic mechanism revisited by electron transfer theories - Publication - Bridge of Knowledge

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Photoinduced electron transfer in 5-bromouracil labeled DNA. A contrathermodynamic mechanism revisited by electron transfer theories

Abstract

The understanding of the 5-bromouracil (BrU) based photosensitization mechanism of DNA damage is of large interest due to the potential applications in photodynamic therapy. Photoinduced electron transfer (ET) in BrU labeled duplexes comprising the 50 -GBrU or 50 -ABrU sequence showed that a much lower reactivity was found for the 50 -GBrU pattern. Since the ionization potential of G is lower than that of A, this sequence selectivity has been dubbed a contrathermodynamic one. In the current work, we employ the Marcus and Marcus–Levich–Jortner theory of ET in order to shed light on the observed effect. By using a combination of Density Functional Theory (DFT) and solvation continuum models, we calculated the electronic couplings, reorganization energies, and thermodynamic stimuli for electron transfer which enabled the rates of forward and back ET to be estimated for the two considered sequences. The calculated rates show that the photoreaction could not be efficient if the ET process proceeded within the considered dimers. Only after introducing additional adenines between G and BrU, which accelerates the forward and slows down the back ET, is a significant amount of photodamage expected.

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Category:
Articles
Type:
artykuł w czasopiśmie wyróżnionym w JCR
Published in:
PHYSICAL CHEMISTRY CHEMICAL PHYSICS no. 21, pages 4387 - 4393,
ISSN: 1463-9076
Language:
English
Publication year:
2019
Bibliographic description:
Cupellini L., Wityk P., Mennucci B., Rak J.: Photoinduced electron transfer in 5-bromouracil labeled DNA. A contrathermodynamic mechanism revisited by electron transfer theories// PHYSICAL CHEMISTRY CHEMICAL PHYSICS. -Vol. 21, nr. 8 (2019), s.4387-4393
DOI:
Digital Object Identifier (open in new tab) 10.1039/c8cp07700b
Verified by:
Gdańsk University of Technology

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