Synthesis of Functionalized Sugar Nucleotide Donors for the Glycan-Microarray-Based Identification and Characterization of Plant Glycosyltransferases

植物细胞壁由一种复杂的复合体组成，这种复合体主要由几个在植物生命周期中具有基本功能的多糖网络组成。这些细胞壁多糖作为可持续材料的来源和生产生物燃料受到了极大的关注。为了提高利用生物质作为可再生资源的经济可行性，产生了越来越多的具有修饰多糖组成的植物。然而，进行有针对性的遗传修饰的一个先决条件是详细了解细胞壁多糖的生物合成。我们最近生产了一种配备合成细胞壁低聚糖的葡聚糖微阵列。该微阵列首次提供了开发同时筛选各种植物糖基转移酶的检测方法的机会。微阵列将与化学合成的叠氮功能化的糖核苷酸和假定的糖基转移酶孵育。任何被掺入叠氮功能化的单糖都将通过随后使用点击化学的荧光染料标记来可视化。因此，这种高通量分析的微阵列形式不仅对鉴定新的糖基转移酶有价值，而且将直接提供关于它们底物特异性的信息。

Plant cell walls consist of a sophisticated composite largely made of several polysaccharide networks with essential functions in the life cycle of the plant. These cell wall polysaccharides receive an enormous interest as sources of sustainable materials and for the production of biofuels. To enhance the economic viability of exploiting biomass as a renewable resource, an increasing number of plants with modified polysaccharide composition are generated. However, a prerequisite to perform targeted genetic modifications is a detailed knowledge of cell wall polysaccharide biosynthesis. We recently produced a glycan microarray equipped with synthetic cell wall oligosaccharides. This microarray provides for the first time the opportunity to develop an assay for the simultaneous screening of various plant glycosyltransferases. The microarray will be incubated with chemically synthesized azido-functionalized sugar nucleotides and putative glycosyltransferases. Any incorporated azido-functionalized monosaccharide will be visualized by subsequent labeling with a fluorescent dye using click-chemistry. Thus, the microarray format of this high-throughput assay will not only be valuable for identifying new glycosyltransferases, but will directly provide information on their substrate specificities.