The effect of solvation on the radiation damage rate constants for adenine

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It is a well known fact, that water plays an important part in almost all biological systems and that inclusion of solvation effects might therefore be of utmost importance in studies of radiation damage to DNA. In the present investigation we have studied the effect of different solvation models in calculations of Gibbs free energies and reaction rates for the reaction between the OH radical and the DNA nucleobase adenine using Density Functional Theory at the ωB97X-D/6-311++G(2df,2pd) level with the Eckart tunneling correction. The solvent, water, has been included through either the implicit polarizable continuum model (PCM) or through explicit modelling of micro-solvation by a single water molecule at the site of reaction as well as the combination of both. Scrutiny of the thermodynamics and kinetics of the individual sub-reactions suggests that the qualitative differences introduced by the solvation models do not significantly alter the conclusions made based solely on simple gas phase calculations. Abstraction of the amine hydrogens H61 and H62 and addition onto C8 are still the most likely reaction pathways.
OriginalsprogEngelsk
TidsskriftChemPhysChem
Vol/bind17
Udgave nummer19
Sider (fra-til)3086–3095
Antal sider10
ISSN1439-4235
DOI
StatusUdgivet - 2016

ID: 163093101