Department of Chemistry, Aarhus University , DK-8000 Aarhus, Denmark.
J Chem Theory Comput. 2016 Apr 12;12(4):1824-32. doi: 10.1021/acs.jctc.5b01187. Epub 2016 Mar 8.
We show by tensor decomposition analyses that the molecular electrostatic potential for amino acid peptide models has an effective rank less than twice the number of atoms. This rank indicates the number of parameters that can be derived from the electrostatic potential in a statistically significant way. Using this as a guideline, we investigate different strategies for deriving a reduced set of atomic charges, dipoles, and quadrupoles capable of reproducing the reference electrostatic potential with a low error. A full combinatorial search of selected parameter subspaces for N-methylacetamide and a cysteine peptide model indicates that there are many different parameter sets capable of providing errors close to that of the global minimum. Among the different reduced multipole parameter sets that have low errors, there is consensus that atoms involved in π-bonding require higher order multipole moments. The possible correlation between multipole parameters is investigated by exhaustive searches of combinations of up to four parameters distributed in all possible ways on all possible atomic sites. These analyses show that there is no advantage in considering combinations of multipoles compared to a simple approach where the importance of each multipole moment is evaluated sequentially. When combined with possible weighting factors related to the computational efficiency of each type of multipole moment, this may provide a systematic strategy for determining a computational efficient representation of the electrostatic component in force field calculations.
我们通过张量分解分析表明，氨基酸肽模型的分子静电势的有效秩小于原子数的两倍。这个秩表示可以从静电势中以统计学上显著的方式得出的参数数量。我们以此为指导，研究了不同的策略，以得出一组能够以低误差重现参考静电势的减少的原子电荷、偶极子和四极子参数。对 N-甲基乙酰胺和半胱氨酸肽模型的选定参数子空间进行的全面组合搜索表明，有许多不同的参数集能够提供接近全局最小值的误差。在具有低误差的不同的简化多极参数集中，人们一致认为涉及π键的原子需要更高阶的多极矩。通过对所有可能原子位置上所有可能方式分布的多达四个参数的组合进行穷尽搜索，研究了多极参数之间的可能相关性。这些分析表明，与简单的方法相比，考虑多极组合没有优势，在简单的方法中，每个多极矩的重要性依次进行评估。当与与每种多极矩的计算效率相关的可能加权因子结合使用时，这可能为确定力场计算中静电分量的计算有效表示提供一种系统的策略。
