CONFORMATION AND DYNAMICS OF POLYSACCHARIDES

本项目使用物理化学的方法来研究 能量择优构象的平衡分布 碳水化合物聚合物和低聚物及其速率和机理 这些分子从一种构象传递到另一种构象。 寡糖和多糖在生物医学中发挥着重要的作用。 细胞识别、信号传递和黏附的过程。细菌 例如，胶囊多糖经常引发一种免疫。 在寄主有机体中的反应，因此在寄主生物体中具有潜在的用途 生产针对病原生物的疫苗。的能力 结构和构象多样性的碳水化合物大分子 使他们成为存储和表达 生物细胞表面的生物信息。一个完整的 对这些过程的理解需要通过以下方式理解过程 哪种糖的特定初级序列表达了它的构象 偏好，稳定偏好构象的相互作用， 以及这些大分子通过的过程和路径 在各种分子形状中，一种构象与另一种构象 均衡分配。 在这个项目中，几种结构简单的葡萄糖聚合物 用核磁共振弛豫和动态流变学研究探头 它们在纳秒和微秒时间尺度上的运动速度。这些 实验得到了理论分析的补充，该分析旨在 在分子的基础上解释可观察到的动力学性质。是这样的 研究探索分子内运动的基本过程，可能 当碳水化合物配体与蛋白质受体相互作用时发生。这个 二维多链螺旋结构的结构与稳定性 用这样的方法研究了微生物多糖的类别 核磁共振光谱、电子和扫描探针显微镜等技术， 光散射、扫描量热和构象模拟。这些 研究旨在阐明该溶剂的性质和强度- 调节的碳水化合物-碳水化合物相互作用决定了 碳水化合物在水介质中的构象。这种碳水化合物-碳水化合物 相互作用也可能参与某些生物识别 流程。

This project uses the methods of physical chemistry to investigate the equilibrium distribution of energetically preferred conformations of carbohydrate polymers and oligomers and the rates and mechanisms by which these molecules pass from one conformation to another. Oligo- and polysaccharides play an important part in the biological processes of cellular recognition, signaling, and adhesion. Bacterial capsular polysaccharides, for example, frequently elicit an immune response in the host organism and, hence, have potential uses in the production of vaccines against pathogenic organisms. The capacity of carbohydrate macromolecules for diversity of structure and conformation makes them ideal candidates for roles in the storage and expression of biological information at the surfaces of biological cells. A full understanding of these processes demands a appreciation of the process by which a particular primary sequence of sugars expresses its conformational preferences, the interactions which stabilize the preferred conformations, and the processes and pathways by which these large molecules pass from one conformation to another among the various molecular shapes in the equilibrium distribution. In this project several structurally simple polymers of glucose are investigated by means of NMR relaxation and dynamic rheology to probe their rates of motion on the nanosecond and microsecond time scales. These experiments are complemented by a theoretical analysis designed to interpret the observable dynamic properties on a molecular basis. Such studies probe the fundamental processes of intramolecular motion that may occur as a carbohydrate ligand interacts with a protein receptor. The structure and stability of multiple-stranded helical structures in two classes of microbial polysaccharides are investigated using such techniques as NMR spectroscopy, electron and scanning probe microscopy, light scattering, scanning calorimetry, and conformational modeling. These studies are designed to elucidate the nature and strength of the solvent- modulated carbohydrate-carbohydrate interactions that determine carbohydrate conformation in aqueous media. Such carbohydrate-carbohydrate interactions may also be involved in certain biological recognition processes.