Synthesis of flavonoid O-pentosides by Escherichia coli through engineering of nucleotide sugar pathways and glycosyltransferase

• Published in: Applied and Environmental Microbiology Vol. 80; no. 9; pp. 2754 - 2762
• Main Authors: Han, So Hyun, Kim, Bong Gyu, Yoon, Jeong A, Chong, Youhoon, Ahn, Joong-Hoon
• Format: Journal Article
• Language: English
• Published: United States American Society for Microbiology 01.05.2014
• Subjects: Arabidopsis - enzymology; Arabidopsis - genetics; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Arabidopsis thaliana; Arabinose - metabolism; Biosynthesis; Biosynthetic Pathways; Biotechnology; Carboxy-Lyases - genetics; Carboxy-Lyases - metabolism; E coli; Enzymes; Escherichia coli; Escherichia coli - genetics; Escherichia coli - metabolism; Flavonoids - chemistry; Flavonoids - metabolism; Flowers & plants; Gene expression; Glycosyltransferases - genetics; Glycosyltransferases - metabolism; Metabolic Engineering; Uridine Diphosphate Glucose Dehydrogenase - genetics; Uridine Diphosphate Glucose Dehydrogenase - metabolism; Uridine Diphosphate Sugars - metabolism; Xylose - metabolism
• DOI: 10.1128/AEM.03797-13
• ISSN: 0099-2240

Plants produce two flavonoid O-pentoses, flavonoid O-xyloside and flavonoid O-arabinoside. However, analyzing their biological properties is difficult because flavonoids are not naturally produced in sufficient quantities. In this study, Escherichia coli was used to synthesize the plant-specific flavonoid O-pentosides quercetin 3-O-xyloside and quercetin 3-O-arabinoside. Two strategies were used. First, E. coli was engineered to express components of the biosynthetic pathways for UDP-xylose and UDP-arabinose. For UDP-xylose biosynthesis, two genes, UXS (UDP-xylose synthase) from Arabidopsis thaliana and ugd (UDP-glucose dehydrogenase) from E. coli, were overexpressed. In addition, the gene encoding ArnA (UDP-l-Ara4N formyltransferase/UDP-GlcA C-4″-decarboxylase), which competes with UXS for UDP-glucuronic acid, was deleted. For UDP-arabinose biosynthesis, UXE (UDP-xylose epimerase) was overexpressed. Next, we engineered UDP-dependent glycosyltransferases (UGTs) to ensure specificity for UDP-xylose and UDP-arabinose. The E. coli strains thus obtained synthesized approximately 160 mg/liter of quercetin 3-O-xyloside and quercetin 3-O-arabinoside.