STRUCTURE FUNCTION RELATIONSHIPS IN POLYSACCHARIDES

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 我们的长期目标是阐明(非晶态)生物聚合物，特别是多糖的分子结构，以及它们与溶剂和溶质分子的相互作用，以及混合多糖中的协同作用，以深入了解它们的功能行为。在这方面，这项建议的主要重点是确定一些具有重要生物学意义和工业用途的多糖的三维结构。我们正在进行的研究将包括但不限于(根据需要)藻类(IOTA、kappa和lambda carrageenans)、细菌(结冷胶类似物和洋葱)、真菌(葡醛酸木甘露聚糖)、植物(鼠李糖醛酸半乳糖甘露聚糖)、木材(半乳甘露聚糖)和二元体系(细菌黄原胶：植物葡甘露聚糖和细菌乙腈：植物葡甘露聚糖)的标本。 这些分子或分子络合物具有形成螺旋结构的固有倾向，只有有限的侧向有序性，因此不能作为单晶生长。因此，纤维衍射是可视化其三维结构的唯一方法。这些结构信息对于了解它们与溶剂和溶质分子的相互作用以及与其他多糖的相互作用是必要的，以便它们在食品和医药应用中的有效利用。这一结果将进一步突出多糖的构象空间，因为它们存在于糖胺聚糖和细胞壁中。 聚合物水溶液在室温下拉伸可得到取向的多晶纤维。用连接原子最小二乘法(LALS)程序建立与衍射谱相一致的分子模型，并进行结构求解。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Our long term goals are to elucidate the molecular structures of (non-crystalline) biopolymers, especially polysaccharides, and their interactions with solvent and solute molecules and the synergistic interactions in mixed polysaccharides towards an in depth understanding of their functional behavior. In this regard, the main thrust of this proposal is centered on determining the three-dimensional structures of a number of biologically important and industrially useful polysaccharides. Our ongoing study will include, but not limited to (as need arises), the specimens from algal (iota, kappa and lambda carrageenans); bacterial (gellan analog and cepacian); fungal (glucuronoxylomannan); plant (rhamnogalacturonan); wood (galactoglucomannan) and a binary system (bacterial xanthan:plant glucomannan and bacterial acetan:plant glucomannan). These molecules or molecular complexes have an inherent tendency to form helical structures with only limited lateral ordering and thus cannot be grown as single crystals. Hence, fiber diffraction is the only method of choice for visualizing their three-dimensional organization. Such structural information is needed for understanding their interactions with solvent and solute molecules and with other polysaccharides for their effective utilization in food and pharmaceutical applications. The results will further highlight the conformational space available to polysaccharides as they occur in glycosaminoglycans and cellular walls. Oriented and polycrystalline fibers will be obtained from aqueous polymer solutions through stretching process at room temperature. Linked-Atom Least-Squares (LALS) program will be used to build the molecular models to be in conformity with the diffraction pattern and to solve the structure.