Fluorinated cellobiose and maltose as stand-ins for energy surface calculations
Fluorinated cellobiose and maltose as stand-ins for energy surface calculations
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DOI：
10.1016/j.tetasy.2004.12.007
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发表时间：
2005-01-24
影响因子：
--
通讯作者：
Csonka, GI
中科院分区：
文献类型：
--
作者：
French, AD;Johnson, GP;Csonka, GI
为了更好地理解二糖构象的计算预测，构建了两个类似物的phi，psi图，其中所有羟基被氟原子取代（F-纤维二糖和F-麦芽糖）。这些分子不允许氢键，但应该比其中氢原子取代外环基团的类似物给出更好的空间表示。采用Hartree Fock和B3 LYP密度泛函量子力学（QM）理论。氟化葡萄糖的优选环形状取决于QM理论的水平，但在有限的phi，psi空间。研究表明，环仍然是C-4（1）的形式。此外，氟原子足够遥远，它们不会影响糖苷键的扭转能。F-纤维二糖图谱可以预测晶体中的构象，但F-麦芽糖图谱的预测性较差。QM F-纤维二糖图谱和纤维二糖本身的MM 4：：QM杂交图谱相似。然而，混合麦芽糖地图有更多的实验构象在其2千卡/摩尔的轮廓比QM F-麦芽糖地图。分子内、残基间氢键的表观平均强度约为3 kcal/mol，基于F-麦芽糖图谱上许多氢键合麦芽糖结构的能量。F-麦芽糖图谱类似于麦芽糖类似物的新QM图谱，其中所有羟基均被氢原子取代。爱思唯尔有限公司出版
To better understand computational predictions of disaccharide conformations, phi,psi maps were constructed for two analogs in which all hydroxyl groups were replaced with fluorine atoms (F-cellobiose and F-maltose). These molecules do not permit hydrogen bonding but should give better steric representation than analogs in which hydrogen atoms replaced exo-cyclic groups. Hartree Fock and B3LYP density functional quantum mechanics (QM) theory were used. The preferred ring shape for fluorinated glucose depends on the level of QM theory, but over the limited phi,psi space that was. studied, the rings remained in the C-4(1) form. Also, fluorine atoms are remote enough that they do not affect the torsional energies for the glycosidic bonds. F-Cellobiose maps were predictive of the conformations in crystals, but F-maltose maps were less so. The QM F-cellobiose map and an MM4::QM hybrid map for cellobiose itself were similar. However, the hybrid maltose map had many more experimental conformations within its 2-kcal/mol contour than did the QM F-maltose map. The apparent mean strength of an intra-molecular, inter-residue hydrogen bond is about 3 kcal/mol, based on the energy for many of the hydrogen bonded maltose structures on the F-maltose map. The F-maltose map was similar to a new QM map for an analog of maltose in which all hydroxyl groups were replaced with hydrogen atoms. Published by Elsevier Ltd.