Open AccessCommunication: UV photoionization of cytosine catalyzed by Ag+
Author(s) -
Martín I. Taccone,
Géraldine Féraud,
Matías Berdakin,
C. DedonderLardeux,
Christophe Jouvet,
Gustavo A. Pino
Publication year - 2015
Publication title -
the journal of chemical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.071
H-Index - 357
eISSN - 1089-7690
pISSN - 0021-9606
DOI - 10.1063/1.4927469
Subject(s) - photoionization , photoexcitation , cytosine , chemistry , photochemistry , ionization , ionization energy , nucleobase , basis set , ion , metal , spectroscopy , dna , atomic physics , density functional theory , computational chemistry , excited state , physics , biochemistry , organic chemistry , quantum mechanics
International audienceThe 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+) changes its electronic properties. By means of UV photofragment spectroscopy of cold ions, it was found that the photoexcitation of the CytAg+ complex at lowenergy (315-282) nm efficiently leads to ionized cytosine (Cyt+) 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+, 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+ could have important implications as point mutation of DNA upon sunlight exposition
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