Conformation and Dynamics of Complex Polysaccharides

用稳定同位素13C和15N进行生物合成富集，将用于一系列复杂多糖和寡糖的构象和动力学的核磁共振和分子建模研究。将分析一系列密切相关结构的数据，以确定特定结构特征（如分支和取代基位置）对复杂多糖的构象和动力学的影响。利用稳定同位素富集样品的策略将为本研究项目提供独特的优势，使通过hmqc - noesi、HCCH TOCSY和定量相干转移等三维异核磁共振方法测量3JCH、3jcc、2JCC和3JHH的精确值成为可能。远距离偶联常数可作为糖苷键的二面角的直接量度。分子模型，包括分子动力学模拟，将用于解释实验NOE和耦合常数数据。稳定同位素的富集将使利用带同位素过滤器的核磁共振波谱技术研究凝集素结合的低聚糖的构象和动力学成为可能。该研究将为了解复杂低聚糖的构象和动力学及其与凝集素、糖苷酶和糖基转移酶等特定结合蛋白的相互作用提供重大改进。提高对低聚糖构象和动力学的理解将对广泛用作食品添加剂的多糖的生物技术以及材料科学的其他应用具有重要意义。＊＊＊

9724113 Bush Biosynthetic enrichment with stable isotopes, 13C and 15N, will be employed in an NMR and molecular modeling study of the conformation and dynamics of a series of complex polysaccharides and oligosaccharides. Data on a collection of closely related structures will be analyzed to determine the influence of specific structural features, such as branching and substituent positions, on the conformation and dynamics of complex polysaccharides. The strategy of enrichment of the samples with stable isotopes will confer unique advantages to this research project, making it possible to measure accurate values of 3JCH, 3 JCC, 2JCC, and 3JHH by 3-dimensional heteronuclear NMR methods such as HMQC-NOESY, HCCH TOCSY and quantitative coherence transfer. Long range coupling constants will serve as a direct measure of the dihedral angle of the glycosidic linkage. Molecular modeling, including molecular dynamics simulation, will be used to interpret the experimental NOE and coupling constant data. Enrichment in stable isotopes will make it possible to study the conformation and dynamics of the oligosaccharides bound to lectins by using NMR spectroscopy with isotope filters. The research will provide a significant improvement in the understanding of conformation and dynamics of complex oligosaccharides and their interaction with specific binding proteins such as lectins, glycosidases and glycosyl transferases. An improved understanding of oligosaccharide conformation and dynamics will be valuable in the biotechnology of polysaccharides, which are widely used as food additives, as well as for other applications in materials science. ***