Berthault P, Duchesne D, Desvaux H, Gilquin B
CEA, Centre d'Etudes de Saclay, DRECAM/Service de Chimie Moléculaire, Gif-sur-Yvette, France.
Carbohydr Res. 1995 Oct 23;276(2):267-87. doi: 10.1016/0008-6215(95)00193-w.
The 3D structure of 6-deoxy-6-L-tyrosinylamidocyclomaltoheptaose, a self-complexing beta-cyclodextrin derivative, was determined by NMR and molecular modelling. The aminoacyl side-chain is included in the cavity and induces chemical-shift variations in the CD proton signals, allowing their complete assignment. Dipolar interactions between protons of the tyrosine ring and internal protons of the cyclodextrin were used to obtain distance constraints. Then 42 structures were calculated from 32 distance constraints--21 shorter than 4 A involve the host-guest interactions--using a simulated annealing procedure. Starting from one of the resulting structures, a 250-ps molecular dynamics simulation was carried out in a waterbox without constraint. The simulation data are in agreement with NMR data such as nOe and ring-current effects. The cyclodextrin part takes an elliptical shape, which tightly fits the aromatic moiety. As a consequence, the respective motion of the host and the guest moieties have the same amplitude and time scale: the self-inclusion complex shows only little flexibility.
通过核磁共振（NMR）和分子建模确定了自络合β-环糊精衍生物6-脱氧-6-L-酪氨酸酰胺基环麦芽七糖的三维结构。氨酰基侧链包含在腔内，并引起环糊精（CD）质子信号的化学位移变化，从而实现其完全归属。利用酪氨酸环质子与环糊精内部质子之间的偶极相互作用来获得距离限制。然后，使用模拟退火程序，根据32个距离限制（21个短于4 Å，涉及主客体相互作用）计算出42个结构。从所得结构之一开始，在无约束的水盒中进行了250 ps的分子动力学模拟。模拟数据与诸如核Overhauser效应（nOe）和环电流效应等NMR数据一致。环糊精部分呈椭圆形，紧密贴合芳香部分。因此，主体和客体部分的各自运动具有相同的幅度和时间尺度：自包合络合物仅显示出很小的灵活性。
