Computational Investigation of Fluoride and Superoxide Radical Anion Interactions with the Thymine Nucleobase
Academic Level at Time of Presentation
Senior
Major
Chemistry
Minor
Mathmatics
List all Project Mentors & Advisor(s)
Dr. Wafaa Fawzy
Presentation Format
Oral Presentation
Abstract/Description
We present the first computational investigation of the intermolecular interactions between the fluoride anion (F⁻) and the superoxide radical anion (O₂⁻) with the thymine nucleobase. Calculations were performed using density functional theory (DFT) with the B3LYP functional and the aug-cc-pVDZ correlation-consistent basis set. Full geometry optimizations were carried out for the thymine–F⁻ and thymine–O₂⁻ complexes, accompanied by radial and angular potential energy surface scans, vibrational frequency analyses, and dissociation energy evaluations. Particular attention was given to proton transfer processes from thymine’s acidic N–H sites to F⁻ and O₂⁻, leading to the formation of hydrogen-bonded and proton-transferred complexes. Comparative analysis between these two hard anionic bases reveals differences in hydrogen-bond strength, site selectivity, and proton-transfer propensity. These results provide new insight into the molecular mechanisms underlying oxidative and anionic nucleobase damage, contributing to a deeper understanding of DNA reactivity with reactive oxygen species (ROS).
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Honors College Senior Thesis Presentations
Computational Investigation of Fluoride and Superoxide Radical Anion Interactions with the Thymine Nucleobase
We present the first computational investigation of the intermolecular interactions between the fluoride anion (F⁻) and the superoxide radical anion (O₂⁻) with the thymine nucleobase. Calculations were performed using density functional theory (DFT) with the B3LYP functional and the aug-cc-pVDZ correlation-consistent basis set. Full geometry optimizations were carried out for the thymine–F⁻ and thymine–O₂⁻ complexes, accompanied by radial and angular potential energy surface scans, vibrational frequency analyses, and dissociation energy evaluations. Particular attention was given to proton transfer processes from thymine’s acidic N–H sites to F⁻ and O₂⁻, leading to the formation of hydrogen-bonded and proton-transferred complexes. Comparative analysis between these two hard anionic bases reveals differences in hydrogen-bond strength, site selectivity, and proton-transfer propensity. These results provide new insight into the molecular mechanisms underlying oxidative and anionic nucleobase damage, contributing to a deeper understanding of DNA reactivity with reactive oxygen species (ROS).