Institute of Physical Chemistry and Electrochemistry, Leibniz University Hannover, 30167 Hannover, Germany.
Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, 5230 Odense, Denmark.
J Phys Chem B. 2022 Jul 28;126(29):5400-5412. doi: 10.1021/acs.jpcb.2c02883. Epub 2022 Jul 14.
We present a novel decomposition scheme for electronic interaction energies based on the flexible formulation of fragmentation schemes through fragment combination ranges (FCRs; , , , 164105). We devise a clear additive decomposition with contribution of nondisjoint fragments and correction terms for overlapping fragments and apply this scheme to the metalloenzyme-substrate complex of a lytic polysaccharide monooxygenase (LPMO) with an oligosaccharide. By this, we further illustrate the straightforward adaptability of the FCR-based schemes to novel systems. Our calculations suggest that the description of the electronic structure is a larger error source than the fragmentation scheme. In particular, we find a large impact of the basis set size on the interaction energies. Still, the introduction of three-body interaction terms in the fragmentation setup improves the agreement to the supermolecular reference. Yet, the qualitative results for the decomposition scheme with two-body terms only largely agree within the investigated electronic-structure approaches and basis sets, which are B97-3c, DFT (TPSS and B3LYP), and MP2 methods. The overlap contributions are found to be small, allowing analysis of the interaction energy into individual amino acid residues: We find a particularly strong interaction between the substrate and the LPMO copper active site.
我们提出了一种新的基于片段组合范围（FCR；,,, 164105）的电子相互作用能分解方案，该方案灵活地构建了片段化方案。我们设计了一个清晰的加和分解，其中包括非不交片段的贡献和重叠片段的修正项，并将该方案应用于溶菌多糖单加氧酶（LPMO）与寡糖的金属酶-底物复合物。通过这种方式，我们进一步说明了基于 FCR 的方案对新系统具有直接的适应性。我们的计算表明，电子结构的描述比片段化方案是更大的误差源。特别是，我们发现基组大小对相互作用能有很大的影响。尽管如此，在片段化设置中引入三体相互作用项可以提高与超分子参考的一致性。然而，仅使用二体项的分解方案的定性结果在研究的电子结构方法和基组内（B97-3c、DFT（TPSS 和 B3LYP）和 MP2 方法）大体上是一致的。发现重叠贡献很小，允许将相互作用能分析为单个氨基酸残基：我们发现底物与 LPMO 铜活性位点之间存在特别强的相互作用。
