The inherent flexibility of carbohydrates is dependent on stereochemical arrangements, and characterization of their influence and importance will give insight into the three-dimensional structure and dynamics. In this study, a β-(1→4)/β-(1→3)-linked glucosyl decasaccharide is experimentally investigated by synchrotron small-angle X-ray scattering from which its radius of gyration (R_g) is obtained. Molecular dynamics (MD) simulations of the decasaccharide show four populated states at each glycosidic linkage, namely, syn- and anti-conformations. The calculated R_g values from the MD simulation reveal that in addition to syn-conformers the presence of anti-ψ conformational states is required to reproduce experimental scattering data, unveiling inherent glycosidic linkage flexibility. The CHARMM36 force field for carbohydrates thus describes the conformational flexibility of the decasaccharide very well and captures the conceptual importance that anti-conformers are to be anticipated at glycosidic linkages of carbohydrates.

中文翻译：

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多个构象态有助于葡聚糖十糖的3D结构：联合的SAXS和MD仿真研究

碳水化合物固有的柔韧性取决于立体化学排列，其影响和重要性的表征将使我们深入了解三维结构和动力学。在这项研究中，通过同步加速器小角X射线散射实验研究了β-（1→4）/β-（1→3）连接的葡糖基十糖，从而获得了其回转半径（R _g）。十糖的分子动力学（MD）模拟在每个糖苷键处显示四个组装状态，即顺式和反式构象。计算的R _gMD模拟的数值表明，除了顺式构象异构体外，还需要抗ψ构象态的存在才能重现实验性散射数据，从而揭示了固有的糖苷键柔性。因此，碳水化合物的CHARMM36力场很好地描述了十糖的构象柔韧性，并捕获了在糖苷键处预期存在抗构象异构体的概念重要性。