Hydrogen-Bonded Double-Proton Transfer in Five Guanine-Cytosine Base Pairs after Hydrogen Atom Addition

作者：Lin Yuexia; Wang Hongyan^*; Gao Simin; Li Ruhu; Schaefer Henry F III

来源：Journal of Physical Chemistry B, 2012, 116(30): 8908-8915.

DOI：10.1021/jp3048746

The double-proton transfer reactions in Watson-rick guanine-cytosine (GC) base pairs after hydrogen atom addition are studied theoretically. The structural changes and energy differences among the structures are compared to explore the double-proton transfer mechanisms, concerted and stepwise. The concerted mechanism is found in all five radicals (GC+H)(center dot) considered, while the stepwise mechanism is predicted only for structures G-(HCC6)-C-center dot and H(center dot)G(N7)-C. The geometrical features have been found to change regularly in the concerted double-proton transfer. This is different from the single-proton transfer, for which the structural perturbations are dispersed throughout the GC base pair. The energy analyses demonstrate that the concerted double-proton transfer mechanism is more favorable in the gas phase, while the stepwise mechanism dominates in water. The structures of proton transfer products become less favored energetically.

• 出版日期2012-8-2
• 单位西南交通大学