Telomere Structure and Stability: Covalency in Hydrogen Bonds, Not Resonance Assistance, Causes Cooperativity in Guanine Quartets
Telomere Structure and Stability: Covalency in Hydrogen Bonds, Not Resonance Assistance, Causes Cooperativity in Guanine Quartets
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DOI：
10.1002/chem.201102234
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发表时间：
2011-11-04
影响因子：
4.3
通讯作者：
Bickelhaupt, F. Matthias
中科院分区：
文献类型：
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作者：
Guerra, Celia Fonseca;Zijlstra, Hester;Bickelhaupt, F. Matthias
我们发现鸟嘌呤四联体中氢键之间的协同增强不是由共振辅助氢键（RAHB）引起的。这是基于色散校正密度泛函理论（DFT-D）对鸟嘌呤四联体（G（4））和黄嘌呤四联体（X-4）进行的广泛计算分析得出的。我们的调查涵盖的情况下，在气相中，在水溶液中，以及在端粒样堆栈的四重态。从定量的Kohn-Sham分子轨道（MO）和相应的能量分解分析（EDA）中提出了鸟嘌呤四联体中氢键协同作用的新机制。我们的分析表明，有趣的协同性起源于电荷分离，伴随着施主-受体轨道相互作用的选择子系统，而不是从加强所造成的共振p-电子系统。这里提出的协同机制被认为适用于，超越本模型系统，也显示协同效应的其他氢键。
We show that the cooperative reinforcement between hydrogen bonds in guanine quartets is not caused by resonance-assisted hydrogen bonding (RAHB). This follows from extensive computational analyses of guanine quartets (G(4)) and xanthine quartets (X-4) based on dispersion-corrected density functional theory (DFT-D). Our investigations cover the situation of quartets in the gas phase, in aqueous solution as well as in telomere-like stacks. A new mechanism for cooperativity between hydrogen bonds in guanine quartets emerges from our quantitative Kohn-Sham molecular orbital (MO) and corresponding energy decomposition analyses (EDA). Our analyses reveal that the intriguing cooperativity originates from the charge separation that goes with donor-acceptor orbital interactions in the selectron system, and not from the strengthening caused by resonance in the p-electron system. The cooperativity mechanism proposed here is argued to apply, beyond the present model systems, also to other hydrogen bonds that show cooperativity effects.