Quantum molecular simulation of the H abstraction at C4′ of DNA sugar moiety by the free radical •OH

The simulation of the H abstraction at the C4' site of the DNA deoxyribose by the hydroxyl radical was conducted using a supermolecular model composed of a sodium compensated-5'pdCp3' molecule in interaction with . OH. The mechanism of the H abstraction is discussed on the basis of various ab initio quantum molecular computations and the obtained Molecular Electrostatic Potentials, frontier orbitals and total spin density. Analysis of the results shows that the hydrogen abstraction by . OH at C4' position on the deoxyribose and H2O formation is a bimolecular transfer reaction in agreement with a diffusion controlled process. (C) 1999 Elsevier Science B.V. All rights reserved.