skip to main content

SciTech ConnectSciTech Connect

Title: Communication: UV photoionization of cytosine catalyzed by Ag{sup +}

The photo-induced damages of DNA in interaction with metal cations, which are found in various environments, still remain to be characterized. In this paper, we show how the complexation of a DNA base (cytosine (Cyt)) with a metal cation (Ag{sup +}) changes its electronic properties. By means of UV photofragment spectroscopy of cold ions, it was found that the photoexcitation of the CytAg{sup +} complex at low energy (315-282) nm efficiently leads to ionized cytosine (Cyt{sup +}) as the single product. This occurs through a charge transfer state in which an electron from the p orbital of Cyt is promoted to Ag{sup +}, as confirmed by ab initio calculations at the TD-DFT/B3LYP and RI-ADC(2) theory level using the SV(P) basis set. The low ionization energy of Cyt in the presence of Ag{sup +} could have important implications as point mutation of DNA upon sunlight exposition.
Authors:
; ;  [1] ; ; ;  [2]
  1. INFIQC (CONICET – Universidad Nacional de Córdoba), Dpto. de Fisicoquímica, Facultad de Ciencias Químicas, Centro Láser de Ciencias Moleculares, Universidad Nacional de Córdoba, Ciudad Universitaria, X5000HUA Córdoba (Argentina)
  2. Physique des Interactions Ioniques et Moléculaires (PIIM): UMR- 7345, CNRS, Aix Marseille Université, 13397 Marseille (France)
Publication Date:
OSTI Identifier:
22493439
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 143; Journal Issue: 4; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CATIONS; COMPLEXES; CYTOSINE; DENSITY FUNCTIONAL METHOD; DNA; ELECTRONS; EXCITATION; GENE MUTATIONS; MOLECULAR IONS; PHOTOIONIZATION; PHOTON-ION COLLISIONS; SILVER COMPLEXES; SILVER IONS; ULTRAVIOLET SPECTRA