Cu2+/+ Cation Coordination to Adenine-Thymine Base Pair. Effects on Intermolecular Proton-Transfer Processes

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• 作者：Marc Noguera ; Juan Bertr&aacute ; n ; Mariona Sodupe
• 刊名：Journal of Physical Chemistry B
• 出版年：2008
• 出版时间：April 17, 2008
• 年：2008
• 卷：112
• 期：15
• 页码：4817 - 4825
• 全文大小：332K
• 年卷期：v.112,no.15(April 17, 2008)
• ISSN：1520-5207

文摘

Intermolecular proton-transfer processes in the Watson & Crick adenine-thymine Cu⁺ and Cu²⁺ cationizedbase pairs have been studied using the density functional theory (DFT) methods. Cationized systems subjectto study are those resulting from cation coordination to the main basic sites of the base pair, N₇ and N₃ ofadenine and O₂ of thymine. For Cu⁺ coordinated to N₇ or N₃ of adenine, only the double proton-transferredproduct is found to be stable, similarly to the neutral system. However, when Cu⁺ interacts with thymine,through the O₂ carbonyl atom, the single proton transfer from thymine to adenine becomes thermodynamicallyspontaneous, and thus rare forms of the DNA bases may spontaneously appear. For Cu²⁺ cation, importanteffects on proton-transfer processes appear due to oxidation of the base pair, which stabilizes the differentsingle proton-transfer products. Results for hydrated systems show that the presence of the water moleculesinteracting with the metal cation (and their mode of coordination) can strongly influence the ability of Cu²⁺to induce oxidation on the base pair.