Three-Dimensional Potential Energy Surface of Selected Carbohydrates' CH/π Dispersion Interactions Calculated by High-Level Quantum Mechanical Methods
Three-Dimensional Potential Energy Surface of Selected Carbohydrates' CH/π Dispersion Interactions Calculated by High-Level Quantum Mechanical Methods
复制标题
DOI：
10.1002/chem.201002876
复制
发表时间：
2011-05-01
影响因子：
4.3
通讯作者：
Koca, Jaroslav
中科院分区：
文献类型：
--
作者：
Kozmon, Stanislav;Matuska, Radek;Koca, Jaroslav
在这项研究中，我们首次对碳水化合物疏水斑块进行系统计算三维扫描，以了解其通过 CH/pi 分散相互作用进行相互作用的能力。研究了碳水化合物β-D-吡喃葡萄糖、β-D-吡喃甘露糖和α-L-吡喃岩藻糖与苯分子的复合物，该复合物作为碳水化合物/蛋白质复合物中CH/pi相互作用的模型。 3D 松弛扫描在 SCC-DFTB-D 水平上进行，碳水化合物疏水侧有 3 757 个网格点。在DFT-D BP/def2-TZVPP级别重新计算所有网格点的相互作用能。获得的结果清楚地显示每个CH基团周围有高度界定和分离的区域，相互作用能高达-5.40 kcal mol(-1)。结果还表明，随着 H 中心点 中心点 pi 距离的增加，这些界定区域合并并形成一个更大的区域，该区域覆盖该特定碳水化合物一侧的所有氢原子。同时，相互作用变得更弱，能量为-2.5 kcal mol(-1)。所有局部能量最小值都在 DFT-D BP/def2-TZVPP 级别上进行了优化，并且这些配合物的相互作用能量通过在 CCSD(T)/CBS 级别上使用高级从头计算进行了细化。优化结果表明CH基氢原子不等价，CCSD(T)/CBS水平的相互作用能范围为-3.54至-5.40 kcal mol(-1)。这些结果还表明，CH/pi色散相互作用的最佳H中心点中心点pi距离约为(2.310+/-0.030)埃，并且定义为碳-氢-苯几何中心的角度为(180+/-30)度。这些结果表明，虽然具有最低相互作用能的色散相互作用相当严格地位于空间中，但相互作用能稍高的区域采用了更大的空间。
In this study we present the first systematic computational three-dimensional scan of carbohydrate hydrophobic patches for the ability to interact through CH/pi dispersion interactions. The carbohydrates beta-D-glucopyranose, beta-D-mannopyranose and alpha-l-fucopyranose were studied in a complex with a benzene molecule, which served as a model of the CH/pi interaction in carbohydrate/protein complexes. The 3D relaxed scans were performed at the SCC-DFTB-D level with 3 757 grid points for both carbohydrate hydrophobic sides. The interaction energy of all grid points was recalculated at the DFT-D BP/def2-TZVPP level. The results obtained clearly show highly delimited and separated areas around each CH group, with an interaction energy up to -5.40 kcal mol(-1). The results also show that with increasing H center dot center dot center dot pi distance these delimited areas merge and form one larger region, which covers all hydrogen atoms on that specific carbohydrate side. Simultaneously, the interaction becomes weaker with an energy of -2.5 kcal mol(-1). All local energy minima were optimized at the DFT-D BP/def2-TZVPP level and the interaction energies of these complexes were refined by use of the high-level ab initio computation at the CCSD(T)/CBS level. Results obtained from the optimization suggest that the CH group hydrogen atoms are not equivalent and the interaction energy at the CCSD(T)/CBS level range from -3.54 to -5.40 kcal mol(-1). These results also reveal that the optimal H center dot center dot center dot pi distance for the CH/pi dispersion interaction is approximately (2.310 +/- 0.030) angstrom, and the angle defined as carbon-hydrogen-benzene geometrical centre is (180 +/- 30)degrees. These results reveal that whereas the dispersion interactions with the lowest interaction energies are quite strictly located in space, the slightly higher interaction energy regions adopt a much larger space.