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Zhang L, Ren S, Liu X, Liu X, Guo F, Sun W, Feng X, Li C. Mining of UDP-glucosyltrfansferases in licorice for controllable glycosylation of pentacyclic triterpenoids. Biotechnol Bioeng 2020; 117:3651-3663. [PMID: 32716052 DOI: 10.1002/bit.27518] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Revised: 07/24/2020] [Accepted: 07/26/2020] [Indexed: 12/18/2022]
Abstract
Pentacyclic triterpenoids have wide applications in the pharmaceutical industry. The precise glucosylation at C-3 OH of pentacyclic triterpenoids mediated by uridine 5'-diphospho-glucosyltransferase (UDP-glucosyltransferase [UGT]) is an important way to produce valuable derivatives with various improved functions. However, most reported UGTs suffer from low regiospecificity toward the OH and COOH groups of pentacyclic triterpenoids, which significantly decreases the reaction efficiency. Here, two new UGTs (UGT73C33 and UGT73F24) were discovered in Glycyrrhiza uralensis. UGT73C33 showed high activity but poor regioselectivity toward the C-3 OH and C-30 COOH of pentacyclic triterpenoid, producing three glucosides. UGT73F24 showed rigid regioselectivity toward C-3 OH of typical pentacyclic triterpenoids producing only C-3 O-glucosylated derivatives. In addition, UGT73C33 and UGT73F24 showed a broad substrate scope toward typical flavonoids with various sugar donors. Next, the substrate recognition mechanism of UGT73F24 toward glycyrrhetinic acid (GA) and UDP-glucose was investigated. Two key residues, I23 and L84, were identified to determine activity, and site-directed mutagenesis of UGT73F24-I23G/L84N increased the activity by 4.1-fold. Furthermore, three in vitro GA glycosylation systems with UDP-recycling were constructed, and high yields of GA-3-O-Glc (1.25 mM), GA-30-O-Glc (0.61 mM), and GA-di-Glc (0.26 mM) were obtained. The de novo biosynthesis of GA-3-O-glucose (26.31 mg/L) was also obtained in engineered yeast.
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Affiliation(s)
- Liang Zhang
- Institute of Biochemical Engineering, Department of Chemical Engineering, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, China
| | - Shichao Ren
- Institute of Biochemical Engineering, Department of Chemical Engineering, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, China
| | - Xiaofei Liu
- Institute of Biochemical Engineering, Department of Chemical Engineering, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, China
| | - Xiaochen Liu
- Institute of Biochemical Engineering, Department of Chemical Engineering, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, China
| | - Fang Guo
- Institute of Biochemical Engineering, Department of Chemical Engineering, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, China
| | - Wentao Sun
- Institute of Biochemical Engineering, Department of Chemical Engineering, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, China
| | - Xudong Feng
- Institute of Biochemical Engineering, Department of Chemical Engineering, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, China
| | - Chun Li
- Institute of Biochemical Engineering, Department of Chemical Engineering, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, China.,Key Laboratory for Industrial Biocatalysis, Ministry of Education, Department of Chemical Engineering, Tsinghua University, Beijing, China
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