Progetti in evidenza
Fondo Europeo Pesca(443 visite)
Fondazione Veronesi(Link esterno)
MFAG Grant(1009 visite)
Adenine radicals generated in alternating AT duplexes by direct absorption of low-energy UV radiation (30 visite)
Faraday Discuss (ISSN: 1359-6640print, 1359-6640linking), 2018 Jan 26; N/D: N/D-N/D.
Tipo di articolo: Journal Article
Impact factor: 4.194
Impact factor a 5 anni: 4.193
Parole chiave: Non disponibili.
Url: Non disponibile.
There is increasing evidence that the direct absorption of photons with energies that are lower than the ionization potential of nucleobases may result in oxidative damage to DNA. The present work, which combines nanosecond transient absorption spectroscopy and quantum mechanical calculations, studies this process in alternating adenine-thymine duplexes (AT)n. We show that the one-photon ionization quantum yield of (AT)10 at 266 nm (4.66 eV) is (1.5 +/- 0.3) x 10(-3). According to our PCM/TD-DFT calculations carried out on model duplexes composed of two base pairs, (AT)1 and (TA)1, simultaneous base pairing and stacking does not induce important changes in the absorption spectra of the adenine radical cation and deprotonated radical. The adenine radicals, thus identified in the time-resolved spectra, disappear with a lifetime of 2.5 ms, giving rise to a reaction product that absorbs at 350 nm. In parallel, the fingerprint of reaction intermediates other than radicals, formed directly from singlet excited states and assigned to AT/TA dimers, is detected at shorter wavelengths. PCM/TD-DFT calculations are carried out to map the pathways leading to such species and to characterize their absorption spectra; we find that, in addition to the path leading to the well-known TA* photoproduct, an AT photo-dimerization path may be operative in duplexes.
*** IBB - CNR ***
LIDYL, CEA, CNRS, Universite Paris-Saclay, F-91191 Gif-sur-Yvette, France. email@example.com firstname.lastname@example.org., Istituto Biostrutture e Bioimmagini - Consiglio Nazionale delle Ricerche, Via Mezzocannone 16, I-80134 Napoli, Italy., LIDYL, CEA, CNRS, Universite Paris-Saclay, F-91191 Gif-sur-Yvette, France. email@example.com firstname.lastname@example.org and Istituto Biostrutture e Bioimmagini - Consiglio Nazionale delle Ricerche, Via Mezzocannone 16, I-80134 Napoli, Italy.,
Esporta in BibTeX Esporta in EndNote
Ultima modifica di Massimiliano Sorbillo in data Tuesday 06 February 2018, 12:53:42
30 visite. Ultima visita in data Friday 27 July 2018, 3:52:03
Nessun bando in corso.
Archivio Concorsi>>> (907 visite)
Nessun evento in programma.
Archivio Eventi>>> (810 visite)