Ali Mohamed Yassin, Chang Qing, Yan Quande, Qian Zheng, Guo Xiang, Thow Kieran, Wu Jinhong, Zhang Yong, Feng Yan
State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China.
Biochemistry Department, Faculty of Agriculture, Fayoum University, Fayoum, Egypt.
Front Bioeng Biotechnol. 2021 Jun 8;9:645079. doi: 10.3389/fbioe.2021.645079. eCollection 2021.
Glycyrrhetinic acid (GA) is a principal bioactive pentacyclic triterpenoid from . Uridine diphosphate-dependent glycosyltransferases (UGTs) have been widely used to catalyze glycosylation of diverse nature products for the development of potential therapeutic compounds. In this study, we have characterized a UGT109A3 from , which can glycosylate both the free C3 hydroxyl and C30 carboxyl groups of GA to yield a unique 3, 30-O-β-D-diglucoside-GA. By coupling the microbial UGT109A3 to plant sucrose synthase (SUS), GA-diglucoside could be biosynthesized in an efficient and economical way. With a fed-batch glycosylation, a large scale of GA-diglucoside (6.26 mM, 4.98 g/L in 8 h) could be enzymatically transformed from GA. The obtained GA-diglucoside showed a significant water solubility improvement of around 3.4 × 10 fold compared with that of the parent GA (29 μM). Moreover, it also exhibited dose-dependent cytotoxicity toward human colon carcinoma Caco-2 cell line according to MTT assay, having an IC at 160 μM. This study not only establishes efficient platform for producing GA-glucosides, but is also valuable for developing further the biosynthesis of other complex glycosylated natural products.
甘草次酸（GA）是一种主要的生物活性五环三萜类化合物。尿苷二磷酸依赖性糖基转移酶（UGTs）已被广泛用于催化多种天然产物的糖基化反应，以开发潜在的治疗性化合物。在本研究中，我们鉴定了一种来自[具体来源未给出]的UGT109A3，它可以将GA的游离C3羟基和C30羧基糖基化，生成一种独特的3,30 - O - β - D - 二葡萄糖苷 - GA。通过将微生物UGT109A3与植物蔗糖合酶（SUS）偶联，可以高效且经济地生物合成GA - 二葡萄糖苷。通过分批补料糖基化反应，可从GA酶法转化得到大量的GA - 二葡萄糖苷（8小时内达到6.26 mM，4.98 g/L）。与母体GA（29 μM）相比，所得的GA - 二葡萄糖苷的水溶性显著提高了约3.4×10倍。此外，根据MTT试验，它对人结肠癌Caco - 2细胞系也表现出剂量依赖性细胞毒性，IC50为160 μM。本研究不仅建立了生产GA - 葡萄糖苷的高效平台，而且对于进一步开发其他复杂糖基化天然产物的生物合成也具有重要价值。
