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

植物细胞壁由复杂的复合物组成，主要由几种多糖网络组成，在植物的生命周期中具有重要功能。这些细胞壁多糖作为可持续材料的来源和用于生产生物燃料受到极大的关注。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改性多糖组合物的植物。然而，进行靶向遗传修饰的先决条件是细胞壁多糖生物合成的详细知识。我们最近制作了一个配备合成细胞壁寡糖的聚糖微阵列。该微阵列首次提供了开发用于同时筛选各种植物糖基转移酶的测定的机会。微阵列将与化学合成的叠氮基官能化的糖核苷酸和推定的糖基转移酶一起孵育。任何并入的叠氮基官能化的单糖将通过随后使用点击化学用荧光染料标记来可视化。因此，这种高通量测定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其底物特异性的信息。

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.