Isolation and characterization of a multifunctional flavonoid glycosyltransferase from Ornithogalum caudatum with glycosidase activity

Shuai Yuan,Jian-Qiang Kong,Ming Liu,Sen Yin

doi:10.1038/s41598-018-24277-3

Shuai Yuan, Jian-Qiang Kong + Show 2 more

Open Access

https://doi.org/10.1038/s41598-018-24277-3

Copy DOI

Abstract

Glycosyltransferases (GTs) are bidirectional biocatalysts catalyzing the glycosylation of diverse molecules. However, the extensive applications of GTs in glycosides formation are limited due to their requirements of expensive nucleotide diphosphate (NDP)-sugars or NDP as the substrates. Here, in an effort to characterize flexible GTs for glycodiversification of natural products, we isolated a cDNA, designated as OcUGT1 from Ornithogalum caudatum, which encoded a flavonoid GT that was able to catalyze the trans-glycosylation reactions, allowing the formation of glycosides without the additions of NDP-sugars or NDP. In addition, OcUGT1 was observed to exhibit additional five types of functions, including classical sugar transfer reaction and three reversible reactions namely NDP-sugar synthesis, sugars exchange and aglycons exchange reactions, as well as enzymatic hydrolysis reaction, suggesting OcUGT1 displays both glycosyltransferase and glycosidase activities. Expression profiles revealed that the expression of OcUGT1 was development-dependent and affected by environmental factors. The unusual multifunctionality of OcUGT1 broadens the applicability of OcUGT1, thereby generating diverse carbohydrate-containing structures.

Highlights

Glycosylation is one of the most important modification reactions, in which sugar moieties are transferred to small molecular acceptors thereby leading to the formation of diverse glycosides with therapeutical potentials[1]
In a screen of novel biocatalysts for flavonoid glycosylations from medicinal plant Ornithogalum caudatum, we found a multifunctional flavonoid GT OcUGT1 exhibiting at least six types of functions, including classical sugar transfer reaction and three reversible reactions namely nucleotide diphosphate (NDP)-sugar synthesis, sugars exchange and aglycons exchange reactions, as well as glycosidase specific hydrolysis and trans-glycosylation reactions
Prior studies revealed that varied flavonoid glycosides, including flavonoid glucosides, galactosides, arabinosides and rutinosides were present in O. caudatum[19,20,21], suggesting the existence of corresponding flavonoid GTs

Summary

Ornithogalum caudatum with glycosidase activity

Glycosyltransferases (GTs) are bidirectional biocatalysts catalyzing the glycosylation of diverse molecules. In a screen of novel biocatalysts for flavonoid glycosylations from medicinal plant Ornithogalum caudatum, we found a multifunctional flavonoid GT OcUGT1 exhibiting at least six types of functions, including classical sugar transfer reaction and three reversible reactions namely NDP-sugar synthesis, sugars exchange and aglycons exchange reactions, as well as glycosidase specific hydrolysis and trans-glycosylation reactions. The unusual multifunctionality of OcUGT1 broadens its applicability, thereby enhancing the glycoconjugates diversity

Results and Discussion

Conclusions

Additional Information