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DNA Nucleobase under Ionizing Radiation: Unexpected Proton Transfer by Thymine Cation in Water Nanodroplets
Author(s) -
Semmeq Abderrahmane,
Badawi Michael,
Hasnaoui Abdellatif,
Ouaskit Said,
Monari Antonio
Publication year - 2020
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.202002025
Subject(s) - nucleobase , thymine , chemistry , deprotonation , ionization , proton , molecular dynamics , chemical physics , ionizing radiation , fragmentation (computing) , dna , molecule , photochemistry , computational chemistry , ion , irradiation , organic chemistry , physics , biochemistry , quantum mechanics , computer science , nuclear physics , operating system
The effect of ionizing radiation on DNA constituents is a widely studied fundamental process using experimental and computational techniques. In particular, radiation effects on nucleobases are usually tackled by mass spectrometry in which the nucleobase is embedded in a water nanodroplet. Here, we present a multiscale theoretical study revealing the effects and the dynamics of water droplets towards neutral and ionized thymine. In particular, by using both hybrid quantum mechanics/molecular mechanics and full ab initio molecular dynamics, we reveal an unexpected proton transfer from thymine cation to a nearby water molecule. This leads to the formation of a neutral radical thymine and a Zundel structure, while the hydrated proton localizes at the interface between the deprotonated thymine and the water droplet. This observation opens entirely novel perspectives concerning the reactivity and further fragmentation of ionized nucleobases.