Topology Controls the Electronic Absorption and Delocalization of Electron Holes in Guanine Quadruplexes

Lara Martinez-Fernandez 1, 2, 3 Akos Banyasz 3, 2 Dimitra Markovitsi 2, 3 Roberto Improta 1, 2, 3
3 DICO - Biomolécules Excitées
IRAMIS - Institut Rayonnement Matière de Saclay, LIDyl - Laboratoire Interactions, Dynamique et Lasers (ex SPAM)
Abstract : Guanine quadruplexes (G4) are four‐stranded DNA structures involved in biological processes and are promising candidates for potential nanotechnological applications. This study examines how the G4 topology affects the electronic absorption and the delocalization of electron holes, which play a key role in charge transport and oxidative damage. Combining transient absorption spectroscopy with PCM/TD‐DFT calculations both parallel (P) and antiparallel (A) G4 are investigated, which are formed, respectively, by association of four TGGGGT strands and folding of the human telomeric sequence GGG(TTAGGG)3. The experimental absorption spectra obtained upon photo‐ionization of A and P are different. This is explained by the different topology of the two G4, as well as by hole delocalization between two stacked guanines, possible only in P+. The spectral signature of delocalized hole in guanine‐rich regions is provided and the chemical physical effects which rule the hole delocalization are discussed.
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Journal articles
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https://hal-cea.archives-ouvertes.fr/cea-01934838
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Submitted on : Monday, November 26, 2018 - 11:55:01 AM
Last modification on : Thursday, February 7, 2019 - 5:15:57 PM

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Lara Martinez-Fernandez, Akos Banyasz, Dimitra Markovitsi, Roberto Improta. Topology Controls the Electronic Absorption and Delocalization of Electron Holes in Guanine Quadruplexes. Chemistry - A European Journal, Wiley-VCH Verlag, 2018, 24 (57), pp.15185 - 15189. ⟨10.1002/chem.201803222⟩. ⟨cea-01934838⟩

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