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Updated: May 10, 2025
Biosynthesis of a Flavonol from a Flavanone by Establishing a One-pot Bienzymatic Cascade
Published on: August 14, 2019
Identification and functional characterization of a new flavonoid glycosyltransferase from Rheum palmatum
Shiwen Zhang1, Jianzhen Zou1, Zitong Hao1
1College of Traditional Chinese Medicine, Hebei University, Baoding 071002, China.
Objective:
To characterize a glycosyltransferase (RpUGT1) from Rheum palmatum and investigate its specificity toward flavonoid compounds.
Methods:
The RpUGT1 was expressed in Escherichia coli and screened for catalytic activity against a range of flavonoid substrates using a high-throughput HPLC assay method. Mass spectrometry (MS) and nuclear magnetic resonance (NMR) were used to determine the structure of the product. Homology modeling, molecular docking analyses and site-directed mutagenesis studies were conducted to identify key residues responsible for its function.
Results:
The recombinant RpUGT1 protein exhibited catalytic activity towards various flavonoids. Notably, RpUGT1 catalyzed the glycosylation of isorhamnetin to form 3-O-glucoside and kaempferol to form 7-O-glucoside, utilizing uridine diphosphate (UDP) glucose as the sugar donor. The homology modeling and molecular docking analyses identified key residues responsible for its activity. Subsequent site-directed mutagenesis studies highlighted the crucial role of K307 in catalysis.
Conclusion:
These discoveries offer valuable perspectives on the role of the UGT family and establish a groundwork for forthcoming research on the synthesis of flavonoids in plants.
