title: Arabidopsis glycosyltransferases as biocatalysts in fermentation for regioselective synthesis of diverse quercetin glucosides.
abstract: Regioselectivity of glycosyltransferases offers an important means to overcome the limitations of chemical synthesis of small molecule glycosides. In this study we explore a large multigene family of UDP-glucose:glycosyltransferases of Arabidopsis for their potential as novel biocatalysts for in vitro synthesis and whole-cell catalysis. We used quercetin as a substrate for this study because the flavonol and its glycosides have important medicinal properties and the metabolite provides a complex structure for regioselective glucosylation. We analyzed the activity of 91 recombinant enzymes for in vitro activity toward quercetin and discovered 29 that are capable of glucosylating the substrate. We demonstrate the first enzymic synthesis of a range of glucosides in vitro, including the 3-O-, 7-O-, 3'-O-, and 4'-O-monoglucosides, 3,7-di-O-glucoside, and 7,3'-di-O-glucoside. We also show that the regioselectivity of glucosylation can be maintained when the enzymes are used as whole-cell biocatalysts in Escherichia coli.
authors.affiliation: Department of Biology, CNAP, Heslington, University of York, York, North Yorkshire YO10 5DD, United Kingdom.
authors.forename: Eng-Kiat
authors.initials: EK
authors.lastname: Lim
authors.forename: David A
authors.initials: DA
authors.lastname: Ashford
authors.forename: Bingkai
authors.initials: B
authors.lastname: Hou
authors.forename: Rosamond G
authors.initials: RG
authors.lastname: Jackson
authors.forename: Dianna J
authors.initials: DJ
authors.lastname: Bowles
mesh_terms: D017360:Arabidopsis / Q000201:enzymology* / Q000254:growth & development; D002851:Chromatography, High Pressure Liquid; D003470:Culture Media; D005285:Fermentation; D005960:Glucosides / Q000096:biosynthesis*; D006031:Glycosylation; D016695:Glycosyltransferases / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D011794:Quercetin / Q000737:chemistry*; D011994:Recombinant Proteins / Q000378:metabolism; D013379:Substrate Specificity; D014532:Uridine Diphosphate Glucose / Q000378:metabolism
chemical_list: D003470:Culture Media; D005960:Glucosides; D011994:Recombinant Proteins; D011794:Quercetin; D016695:Glycosyltransferases; D014532:Uridine Diphosphate Glucose