Directional Dependence of Hydrogen Bonds: a Density-based Energy Decomposition Analysis and Its Implications on Force Field Development.
Directional Dependence of Hydrogen Bonds: a Density-based Energy Decomposition Analysis and Its Implications on Force Field Development.
复制标题
氢键的方向依赖性：基于密度的能量分解分析及其对力场发展的影响。
DOI：
10.1021/ct2003226
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发表时间：
2011
影响因子：
5.5
通讯作者：
Zhang,Yingkai
中科院分区：
文献类型：
--
作者：
Lu,Zhenyu;Zhou,Nengjie;Wu,Qin;Zhang,Yingkai
广泛使用的生物分子力场的一个众所周知的缺点是氢键（HB）方向依赖性的描述。在这里，我们的目标是更好地理解这一困难的根源，从而为进一步的力场发展提供一些指导。我们的理论方法集中在一种新颖的基于密度的能量分解分析（DEDA）方法（J.Chem.Phys.2009,131, 164112），其中通过约束搜索来变化地确定冻结密度能量。 DEDA 的这一独特且最重要的特征使我们能够发现冻结密度相互作用项是决定 HB 方向的关键因素，而极化和电荷转移分量之和显示出非常小的 HB 方向依赖性。这一新见解表明，当前不可极化力场难以描述 HB 方向依赖性并不是由于缺乏明确的极化或电荷转移项。以 DEDA 结果为参考，我们进一步证明，原子点电荷模型的主要故障可以通过引入额外的电荷位点或高阶多极矩来很大程度上克服。在所有探索的静电模型中，弥散电荷分布多极模型（最高至四极）也考虑了电荷穿透效应，与相应的 DEDA 结果最为一致。同时，我们的结果表明范德华相互作用项需要进一步改进以更好地模型定向 HB。
One well-known shortcoming of widely used biomolecular force fields is the description of the directional dependence of hydrogen bonding (HB). Here we aim to better understand the origin of this difficulty and thus provide some guidance for further force field development. Our theoretical approaches center on a novel density-based energy decomposition analysis (DEDA) method (J.Chem.Phys.2009,131, 164112), in which the frozen density energy is variationally determined through constrained search. This unique and most significant feature of DEDA enables us to find that the frozen density interaction term is the key factor in determining the HB orientation, while the sum of polarization and charge-transfer components shows very little HB directional dependence. This new insight suggests that the difficulty for current nonpolarizable force fields to describe the HB directional dependence is not due to the lack of explicit polarization or charge-transfer terms. Using the DEDA results as reference, we further demonstrate that the main failure coming from the atomic point charge model can be overcome largely by introducing extra charge sites or higher order multipole moments. Among all the electrostatic models explored, the smeared charge distributed multipole model (up to quadrupole), which also takes account of charge penetration effects, gives the best agreement with the corresponding DEDA results. Meanwhile, our results indicate that the van der Waals interaction term needs to be further improved to better model directional HB.