The importance of conformational rigidity on macroscopic rheological properties was revealed using two model polysaccharides, namely, xanthan gum and hyaluronic acid. Xanthan gum has a rigid tertiary conformation due to its ordered double-helical structure, and the interactions between the tertiary structures result in the formation of a network/quaternary structure. In comparison, hyaluronic acid possesses a relatively flexible tertiary conformation due to its secondary random coil structure. Xanthan gum exhibits a much stronger shear thinning and more solidlike behavior compared to hyaluronic acid, owing to its network/quaternary structure. The rigid tertiary structure and the presence of a network/quaternary structure also endow xanthan gum with better resistance against environmental changes (e.g., salt and/or urea addition, temperature change) compared to hyaluronic acid. The network/quaternary structure allows xanthan gum to form gels with chitosan via electrostatic interactions when using the vapor-induced gelation technique, which is not possible for hyaluronic acid due to its flexible tertiary conformation under similar conditions.

中文翻译：

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了解构象刚性对多糖基混合水凝胶的流变行为和形成的影响

使用两种模型多糖，即黄原胶和透明质酸，揭示了构象刚性对宏观流变学特性的重要性。黄原胶由于其有序的双螺旋结构而具有刚性的三级构象，三级结构之间的相互作用导致形成网络/四级结构。相比之下，透明质酸由于其二级无规卷曲结构而具有相对灵活的三级构象。由于其网络/四级结构，与透明质酸相比，黄原胶表现出更强的剪切稀化和更像固体的行为。刚性三级结构和网络/四级结构的存在也赋予黄原胶更好的抵抗环境变化的能力（例如.例如，盐和/或尿素添加、温度变化）与透明质酸相比。当使用蒸汽诱导凝胶化技术时，网络/四级结构允许黄原胶通过静电相互作用与壳聚糖形成凝胶，这对于透明质酸是不可能的，因为它在类似条件下具有灵活的三级构象。