Waterhouse A L, Calub T M, French A D
Department of Chemistry, Tulane University, New Orleans, Louisiana 70118.
Carbohydr Res. 1991 Sep 18;217:29-42. doi: 10.1016/0008-6215(91)84114-t.
Models of the trisaccharide, 1-kestose [beta-D-fructofuranosyl-(2----1)-beta-D-fructofuranosyl-(2 in equilibrium with 1)-alpha-D -glucopyranoside], were analyzed with the molecular mechanics computer program MM2(87) to ascertain their inter-ring torsion angles, primary alcohol side-group orientations, and ring puckering. The most striking result was that the modeling predicted and n.m.r. spectroscopy corroborated that the central fructofuranose ring takes a different form from that previously observed in the crystal. No other studies of fructofuranoses have observed that crystallographic form, thus suggesting that the 18 hydrogen bonds created upon crystallization of 1-kestose support the ring deformation. Because this trisaccharide is too complex for a complete study of conformation space, only structures having inter-ring conformations that were at energetic valleys in previous studies of the constituent disaccharides were analyzed. The model of the model disaccharides, although they were generally close to the linkage conformations observed in the crystal structure, differing by an average of 19 degrees.
利用分子力学计算机程序MM2(87)对三糖1-蔗果三糖[β-D-呋喃果糖基-(2→1)-β-D-呋喃果糖基-(2与1处于平衡状态)-α-D-吡喃葡萄糖苷]的模型进行了分析，以确定其环间扭转角、伯醇侧基取向和环的褶皱情况。最显著的结果是，建模预测且核磁共振光谱证实，中心呋喃果糖环呈现出与之前在晶体中观察到的不同形式。对呋喃果糖的其他研究均未观察到那种晶体形式，因此表明1-蔗果三糖结晶时形成的18个氢键支持了环的变形。由于这种三糖过于复杂，无法对构象空间进行全面研究，所以仅分析了那些环间构象处于之前对组成二糖研究中能量谷的结构。模型二糖的模型，尽管它们通常与晶体结构中观察到的连接构象接近，但平均相差19度。
