Protonation of thymine, cytosine, adenine, and guanine DNA nucleic acid bases: Theoretical investigation into the framework of density functional theory
✍ Scribed by Russo, Nino; Toscano, Marirosa; Grand, Andr�; Jolibois, Franck
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 336 KB
- Volume
- 19
- Category
- Article
- ISSN
- 0192-8651
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✦ Synopsis
Gradient-corrected density functional computations with triplezeta-type basis sets were performed to determine the preferred protonation site and the absolute gas-phase proton affinities of the most stable tautomer of the Ž . Ž . Ž . Ž . DNA bases thymine T , cytosine C , adenine A , and guanine G . Charge distribution, bond orders, and molecular electrostatic potentials were considered to rationalize the obtained results. The vibrational frequencies and the contribution of the zero-point energies were also computed. Significant geometrical changes in bond lengths and angles near the protonation sites were Ž . Ž . Ž . found. At 298 K, proton affinities values of 208.8 T , 229.1 C , 225.8 A , and Ž . 230.3 G kcalrmol were obtained in agreement with experimental results.