The photoactivated dynamics of dGpdC and dCpdG sequences in DNA: a comprehensive quantum mechanical study

Martínez-Fernández, Lara; Green, James Alexander; Esposito, Luciana; Jouybari, Martha Yaghoubi; Zhang, Yuyuan; Santoro, Fabrizio; Kohler, Bern; Improta, Roberto

doi:10.1039/d4sc00910j

Cited by 3 publications

(1 citation statement)

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“…Numerous transient absorption ( TA ) studies have characterized the decay of CT states in various types of DNA multimers, ranging from dinucleotides and single strands to duplexes and guanine quadruplexes (G-Quadruplexes). 8–22 However, the formation of these states from the excited states initially populated upon photon absorption (Franck–Condon states) has not been observed in real time. Likewise, ET was inferred from the fluorescence anisotropy values detected once the process has occurred.…”

Section: Introductionmentioning

confidence: 99%

Real-time observation of sub-100-fs charge and energy transfer processes in DNA dinucleotides

Petropoulos,

Martinez-Fernandez,

Uboldi

et al. 2024

Chem. Sci.

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Section: Introductionmentioning

confidence: 99%

Real-time observation of sub-100-fs charge and energy transfer processes in DNA dinucleotides

Petropoulos,

Martinez-Fernandez,

Uboldi

et al. 2024

Chem. Sci.

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Computational Studies on Photoinduced Charge Transfer Processes in Nucleic Acids: From Watson–Crick Dimers to Quadruple Helices

Fernández,

Improta

2024

Nucleic Acids and Molecular Biology

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Factors Affecting the Population of Excited Charge Transfer States in Adenine/Guanine Dinucleotides: A Joint Computational and Transient Absorption Study

Petropoulos,

Martinez-Fernandez,

Uboldi

et al. 2024

Biomolecules

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There is compelling evidence that the absorption of low-energy UV radiation directly by DNA in solution generates guanine radicals with quantum yields that are strongly dependent on the secondary structure. Key players in this unexpected phenomenon are the photo-induced charge transfer (CT) states, in which an electric charge has been transferred from one nucleobase to another. The present work examines the factors affecting the population of these states during electronic relaxation. It focuses on two dinucleotides with opposite orientation: 5′-dApdG-3′ (AG) and 5′-dGpdA-3′ (GA). Quantum chemistry calculations determine their ground state geometry and the associated Franck–Condon states, map their relaxation pathways leading to excited state minima, and compute their absorption spectra. It has been shown that the most stable conformer is anti-syn for AG and anti-anti for GA. The ground state geometry governs both the excited states populated upon UV photon absorption and the type of excited state minima reached during their relaxation. Their fingerprints are detected in the transient absorption spectra recorded with excitation at 266 nm and a time resolution of 30 fs. Our measurements reveal that in the large majority of dinucleotides, chromophore coupling is already operative in the ground state and that the charge transfer process occurs within ~120 fs. The competition among various relaxation pathways affects the quantum yields of the CT state formation in each dinucleotide, which are estimated to be 0.18 and 0.32 for AG and GA, respectively.

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The photoactivated dynamics of dGpdC and dCpdG sequences in DNA: a comprehensive quantum mechanical study

Abstract: Study of alternating DNA GC sequences by different time-resolved spectroscopies has provided fundamental information on the interaction between UV light and DNA, a process of great biological importance. Multiple decay...

Cited by 3 publications

References 87 publications

Real-time observation of sub-100-fs charge and energy transfer processes in DNA dinucleotides

Real-time observation of sub-100-fs charge and energy transfer processes in DNA dinucleotides

Computational Studies on Photoinduced Charge Transfer Processes in Nucleic Acids: From Watson–Crick Dimers to Quadruple Helices

Factors Affecting the Population of Excited Charge Transfer States in Adenine/Guanine Dinucleotides: A Joint Computational and Transient Absorption Study

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