STRUCTURE FUNCTION RELATIONSHIPS IN POLYSACCHARIDES

这个子项目是众多研究子项目之一

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.