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Unified Description of Ultrafast Excited State Decay Processes in Epigenetic Deoxycytidine Derivatives.

Piotr KabacińskiMarco RomanelliEveliina PonkkonenVishal Kumar JaiswalThomas CarellMarco GaravelliGiulio CerulloIrene Conti
Published in: The journal of physical chemistry letters (2021)
Epigenetic DNA modifications play a fundamental role in modulating gene expression and regulating cellular and developmental biological processes, thereby forming a second layer of information in DNA. The epigenetic 2'-deoxycytidine modification 5-methyl-2'-deoxycytidine, together with its enzymatic oxidation products (5-hydroxymethyl-2'-deoxycytidine, 5-formyl-2'-deoxycytidine, and 5-carboxyl-2'-deoxycytidine), are closely related to deactivation and reactivation of DNA transcription. Here, we combine sub-30-fs transient absorption spectroscopy with high-level correlated multiconfigurational CASPT2/MM computational methods, explicitly including the solvent, to obtain a unified picture of the photophysics of deoxycytidine-derived epigenetic DNA nucleosides. We assign all the observed time constants and identify the excited state relaxation pathways, including the competition of intersystem crossing and internal conversion for 5-formyl-2'-deoxycytidine and ballistic decay to the ground state for 5-carboxy-2'-deoxycytidine. Our work contributes to shed light on the role of epigenetic derivatives in DNA photodamage as well as on their possible therapeutic use.
Keyphrases
  • gene expression
  • single molecule
  • dna methylation
  • circulating tumor
  • cell free
  • hydrogen peroxide
  • mass spectrometry
  • drug induced