The State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 38 Xueyuan Road, Beijing, 100191, China.
The State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 38 Xueyuan Road, Beijing, 100191, China.
Biochem Biophys Res Commun. 2019 Mar 5;510(2):315-321. doi: 10.1016/j.bbrc.2019.01.099. Epub 2019 Jan 30.
Lotus (Nelumbo nucifera Gaertn.), one of the earliest plants in angiosperms, is a perennial aquatic herb widely distributed throughout Eastern Asia. Quercetin and its glycosides are the most abundant phenolic compounds in lotus with multiple pharmacological activities. Although many flavonoid O-glycosyltransferases involved in the biosynthesis of quercetin glycosides have been identified from terrestrial plants, no glycosyltransferase has been identified in aquatic plants. In this study, a new glycosyltransferase (NpUGT6) was identified from the embryo of Nelumbo nucifera (Nelumbinis Plumula). Function characterization demonstrated that NpUGT6 exhibited a robust capability to regio- and stereo-specific O-glycosylation at the 3-hydroxy group of quercetin scaffolds with UDP-glucose. Moreover, the O-glycosylation catalyzed by NpUGT6 was reversible. NpUGT6 is the first identified flavonoid O-glycosyltransferase from aquatic plants. Its sequence will provide useful guidance for the discovery of additional flavonoid glycosyltransferses in Nymphaeaceae and other aquatic plants.
荷花（Nelumbo nucifera Gaertn.）是被子植物中最早的植物之一，是一种广泛分布于东亚的多年生水生草本植物。槲皮素及其糖苷是荷花中最丰富的酚类化合物，具有多种药理活性。尽管已经从陆地植物中鉴定出许多参与槲皮素糖苷生物合成的类黄酮 O-糖基转移酶，但在水生植物中尚未鉴定出糖基转移酶。在这项研究中，从荷花（Nelumbinis Plumula）的胚中鉴定出一种新的糖基转移酶（NpUGT6）。功能表征表明，NpUGT6 具有在槲皮素支架的 3-羟基上进行区域和立体特异性 O-糖基化的强大能力，使用 UDP-葡萄糖。此外，NpUGT6 催化的 O-糖基化是可逆的。NpUGT6 是首次从水生植物中鉴定出的类黄酮 O-糖基转移酶。其序列将为在睡莲科和其他水生植物中发现其他类黄酮糖基转移酶提供有用的指导。
