Theoretical study on the mechanism of the DNA repair protein Fpg

摘要

In this article, theoretical and calculational study at the DFT and ONIOM level are carried out on the Fpg glycosylase catalytic mechanism, to answer some mechanistic questions unclear yet. Representative S_N2 mechanism has been confirmed for all the models. The value 21.35 kcal/mol of the intrinsic activation barrier computed by the ONIOM (BP86/6-311G**:AM1) approach agrees quite well with the experimental result of 20.66 kcal/mol. It has been found out that the electrostatic interaction between the positively charged Arg222 residue and the electronegative oxoG base is the most important influence on the excision process.