1. The Influence of Clustered DNA Damage Containing Iz/Oz and OXO dG on the Charge Transfer through the Double Helix: A Theoretical Study.
- Author
-
Karwowski BT
- Subjects
- Oxazolone chemistry, 8-Hydroxy-2'-Deoxyguanosine chemistry, DNA chemistry, Models, Molecular, Deoxyguanosine chemistry, Deoxyguanosine analogs & derivatives, Thermodynamics, DNA Damage, Imidazoles chemistry
- Abstract
The genome-the source of life and platform of evolution-is continuously exposed to harmful factors, both extra- and intra-cellular. Their activity causes different types of DNA damage, with approximately 80 different types of lesions having been identified so far. In this paper, the influence of a clustered DNA damage site containing imidazolone (Iz) or oxazolone (Oz) and 7,8-dihydro-8-oxo-2'-deoxyguanosine (
OXO dG) on the charge transfer through the double helix as well as their electronic properties were investigated. To this end, the structures of oligo-Iz , d[A1 Iz2 A3 OXO G4 A5 ]*d[T5 C4 T3 C2 T1 ], and oligo-Oz , d[A1 Oz2 A3 OXO G4 A5 ]*d[T5 C4 T3 C2 T1 ], were optimized at the M06-2X/6-D95**//M06-2X/sto-3G level of theory in the aqueous phase using the ONIOM methodology; all the discussed energies were obtained at the M06-2X/6-31++G** level of theory. The non-equilibrated and equilibrated solvent-solute interactions were taken into consideration. The following results were found: (A) In all the discussed cases,OXO dG showed a higher predisposition to radical cation formation, and B) the excess electron migration toward Iz and Oz was preferred. However, in the case of oligo-Oz , the electron transfer from Oz2 to complementary C4 was noted during vertical to adiabatic anion relaxation, while for oligo-Iz , it was settled exclusively on the Iz2 moiety. The above was reflected in the charge transfer rate constant, vertical/adiabatic ionization potential, and electron affinity energy values, as well as the charge and spin distribution. It can be postulated that imidazolone moiety formation within the CDL ds-oligo structure and its conversion to oxazolone can significantly influence the charge migration process, depending on the C2 carbon hybridization sp2 or sp3 . The above can confuse the single DNA damage recognition and removal processes, cause an increase in mutagenesis, and harm the effectiveness of anticancer therapy.- Published
- 2024
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