DNA owes its remarkable photostability to its building blocks—the nucleosides—that efficiently dissipate the energy acquired upon ultraviolet light absorption. The mechanism occurring on a sub-picosecond time scale has been a matter of intense debate. Here we combine sub-30-fs transient absorption spectroscopy experiments with broad spectral coverage and state-of-the-art mixed quantum-classical dynamics with spectral signal simulations to resolve the early steps of the deactivation mechanisms of uridine (Urd) and 5-methyluridine (5mUrd) in aqueous solution. We track the wave packet motion from the Franck-Condon region to the conical intersections (CIs) with the ground state and observe spectral signatures of excited-state vibrational modes. 5mUrd exhibits an order of magnitude longer lifetime with respect to Urd due to the solvent reorganization needed to facilitate bulky methyl group motions leading to the CI. This activates potentially lesion-inducing dynamics such as ring opening. Involvement of the 1nπ* state is found to be negligible.

Tracking excited state decay mechanisms of pyrimidine nucleosides in real time / Borrego-Varillas R.; Nenov A.; Kabacinski P.; Conti I.; Ganzer L.; Oriana A.; Jaiswal V.K.; Delfino I.; Weingart O.; Manzoni C.; Rivalta I.; Garavelli M.; Cerullo G.. - In: NATURE COMMUNICATIONS. - ISSN 2041-1723. - ELETTRONICO. - 12:(2021), pp. 7285.1-7285.7. [10.1038/s41467-021-27535-7]

Tracking excited state decay mechanisms of pyrimidine nucleosides in real time

Nenov A.;Conti I.;Jaiswal V. K.;Rivalta I.;Garavelli M.
;
2021

Abstract

DNA owes its remarkable photostability to its building blocks—the nucleosides—that efficiently dissipate the energy acquired upon ultraviolet light absorption. The mechanism occurring on a sub-picosecond time scale has been a matter of intense debate. Here we combine sub-30-fs transient absorption spectroscopy experiments with broad spectral coverage and state-of-the-art mixed quantum-classical dynamics with spectral signal simulations to resolve the early steps of the deactivation mechanisms of uridine (Urd) and 5-methyluridine (5mUrd) in aqueous solution. We track the wave packet motion from the Franck-Condon region to the conical intersections (CIs) with the ground state and observe spectral signatures of excited-state vibrational modes. 5mUrd exhibits an order of magnitude longer lifetime with respect to Urd due to the solvent reorganization needed to facilitate bulky methyl group motions leading to the CI. This activates potentially lesion-inducing dynamics such as ring opening. Involvement of the 1nπ* state is found to be negligible.
2021
Tracking excited state decay mechanisms of pyrimidine nucleosides in real time / Borrego-Varillas R.; Nenov A.; Kabacinski P.; Conti I.; Ganzer L.; Oriana A.; Jaiswal V.K.; Delfino I.; Weingart O.; Manzoni C.; Rivalta I.; Garavelli M.; Cerullo G.. - In: NATURE COMMUNICATIONS. - ISSN 2041-1723. - ELETTRONICO. - 12:(2021), pp. 7285.1-7285.7. [10.1038/s41467-021-27535-7]
Borrego-Varillas R.; Nenov A.; Kabacinski P.; Conti I.; Ganzer L.; Oriana A.; Jaiswal V.K.; Delfino I.; Weingart O.; Manzoni C.; Rivalta I.; Garavelli M.; Cerullo G.
File in questo prodotto:
File Dimensione Formato  
NatureComm2021.pdf

accesso aperto

Descrizione: Main Text
Tipo: Versione (PDF) editoriale
Licenza: Licenza per Accesso Aperto. Creative Commons Attribuzione (CCBY)
Dimensione 857.55 kB
Formato Adobe PDF
857.55 kB Adobe PDF Visualizza/Apri
SupplementaryInformation.pdf

accesso aperto

Descrizione: Supplementary Information
Tipo: File Supplementare
Licenza: Licenza per Accesso Aperto. Creative Commons Attribuzione (CCBY)
Dimensione 17.73 MB
Formato Adobe PDF
17.73 MB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/844548
Citazioni
  • ???jsp.display-item.citation.pmc??? 11
  • Scopus 34
  • ???jsp.display-item.citation.isi??? 23
social impact