Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College (State Key Laboratory of Bioactive Substance and Function of Natural Medicines & Ministry of Health Key Laboratory of Biosynthesis of Natural Products), Beijing, 100050, China.
Sci Rep. 2018 Apr 12;8(1):5886. doi: 10.1038/s41598-018-24277-3.
Glycosyltransferases (GTs) are bidirectional biocatalysts catalyzing the glycosylation of diverse molecules. However, the extensive applications of GTs in glycosides formation are limited due to their requirements of expensive nucleotide diphosphate (NDP)-sugars or NDP as the substrates. Here, in an effort to characterize flexible GTs for glycodiversification of natural products, we isolated a cDNA, designated as OcUGT1 from Ornithogalum caudatum, which encoded a flavonoid GT that was able to catalyze the trans-glycosylation reactions, allowing the formation of glycosides without the additions of NDP-sugars or NDP. In addition, OcUGT1 was observed to exhibit additional five types of functions, including classical sugar transfer reaction and three reversible reactions namely NDP-sugar synthesis, sugars exchange and aglycons exchange reactions, as well as enzymatic hydrolysis reaction, suggesting OcUGT1 displays both glycosyltransferase and glycosidase activities. Expression profiles revealed that the expression of OcUGT1 was development-dependent and affected by environmental factors. The unusual multifunctionality of OcUGT1 broadens the applicability of OcUGT1, thereby generating diverse carbohydrate-containing structures.
糖基转移酶（GTs）是一种双向生物催化剂，能够催化多种分子的糖基化反应。然而，由于其需要昂贵的核苷酸二磷酸（NDP）-糖或 NDP 作为底物，GTs 在糖苷形成中的广泛应用受到限制。在这里，我们努力研究灵活的 GTs，以实现天然产物的糖基多样化，从朱顶红（Ornithogalum caudatum）中分离出一个 cDNA，命名为 OcUGT1，它编码一种类黄酮 GT，能够催化反式糖基化反应，无需添加 NDP-糖或 NDP 即可形成糖苷。此外，OcUGT1 还表现出另外五种类型的功能，包括经典的糖基转移反应和三种可逆反应，即 NDP-糖合成、糖交换和糖苷交换反应，以及酶解反应，表明 OcUGT1 同时具有糖基转移酶和糖苷酶的活性。表达谱分析表明，OcUGT1 的表达依赖于发育阶段，并受环境因素的影响。OcUGT1 的异常多功能性拓宽了 OcUGT1 的适用性，从而产生了多种含有碳水化合物的结构。
