Density Functional Study toward Understanding Dehydrogenation of the Adenine-Thymine Base Pair and Its Anion

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• 作者：Hujun Xie ; Fei Xia ; Zexing Cao
• 刊名：Journal of Physical Chemistry A
• 出版年：2007
• 出版时间：May 24, 2007
• 年：2007
• 卷：111
• 期：20
• 页码：4384 - 4390
• 全文大小：362K
• 年卷期：v.111,no.20(May 24, 2007)
• ISSN：1520-5215

文摘

The dehydrogenated radicals and anions of Watson-Crick adenine-thymine (A-T) base pair have beeninvestigated by the B3LYP/DZP++ approach. Calculations show that the dehydrogenated radicals andanions have relatively high stabilities compared with the single base adenine and thymine. The electronattachment to the A-T base pair and its derivatives significantly modifies the hydrogen bond interactionsand results in remarkable structural changes. As for the dehydrogenated A-T radicals, they have relativelyhigh electron affinities and different dehydrogenation properties with respect to their constituent elements.The relatively low-cost hydrogen eliminations correspond to the (N9)-H (adenine) and (N1)-H (thymine)bonds cleavage. Both dehydrogenation processes have Gibbs free energies of reaction G of 13.4 and 17.2kcal mol^-1, respectively. The solvent water exhibits significant effect on electron attachment and dehydrogenation properties of the A-T base pair and its derivatives. In the dehydrogenating process, the anionicA-T fragment gradually changes its electronic configuration from * to * state, like the single bases adenineand thymine.