Synthesis of plant carbohydrates and their biological application

一个多世纪以来，生产燃料、化学品和许多材料的主要碳源一直是化石资源。最近，从非食用生物质中提取的植物多糖已经成为一种很有前途的可再生替代品，可能会取代很大一部分石油产品。然而，为了进一步提高植物生物量的经济价值，必须更详细地了解植物多糖的分子结构、功能和生物合成。在我的艾美诺特研究小组的帮助下，我们化学合成了植物多糖，将其作为细胞壁生物学的分子工具。我们成功地建立了不同类型细胞壁多糖的自动化固相合成，并获得了超过65种合成寡糖的集合。事实证明，这些葡聚糖对于表征细胞壁糖链导向抗体和细胞壁降解和修饰酶非常有用。我们还通过化学-酶法制备了人工阿拉伯木聚糖，与天然多糖不同，这种多糖具有完全规则的取代模式。在下一个资助期，我们将继续努力，通过合成复杂的果胶低聚糖，获得一个合成细胞壁低聚糖的文库。果胶是自然界中最复杂的多糖，含有大量稀有单糖和不寻常的糖苷键。此外，我们将扩大我们成功的研究项目，将人工阿拉伯木聚糖多糖的化学-酶合成扩展到纤维素、木聚糖和半乳聚糖，这些多糖都装饰着明确的非天然取代基图案。这些多糖将被用于结构-性质关系研究，而不能用不同种类的天然样品进行研究。

For more than a century the primary carbon source for the production of fuels, chemicals and many materials has been fossil resources. Recently, plant polysaccharides from non-food biomass have emerged as a promising renewable alternative that may displace a significant fraction of petroleum-derived products. However, the molecular structures, functions and biosyntheses of plant polysaccharides must be understood in greater detail to further enhance the economic value of plant biomass. With my Emmy Noether research group we chemically synthesize plant glycans as defined molecular tools for cell wall biology. We successfully established the automated solid-phase synthesis of different classes of cell wall glycans and obtained a collection of more than 65 synthetic oligosaccharides. These glycans proved very useful for the characterization of cell wall glycan-directed antibodies and cell wall-degrading and -modifying enzymes. We also chemo-enzymatically prepared artificial arabinoxylan polysaccharides that have, unlike their natural counterparts, a fully regular substitution pattern. In the next funding period we will continue our efforts towards procuring a library of synthetic cell wall oligosaccharides by synthesizing complex pectic oligosaccharides. Pectin is the most complex polysaccharide in nature containing a large number of rare monosaccharides and unusual glycosidic linkages. Furthermore, we will expand our successful research program towards the chemo-enzymatic synthesis of artificial arabinoxylan polysaccharides to cellulose, xylan, and galactan polysaccharides that are decorated with well-defined patterns of unnatural substituents. These polysaccharides will be explored for structure-property relationship studies that cannot be performed with heterogeneous natural samples.