Novel Glycosylation by Amylosucrase to Produce Glycoside Anomers

Abstract

Glycosylation occurring at either lipids, proteins, or sugars plays important roles in many biological systems. In nature, enzymatic glycosylation is the formation of a glycosidic bond between the anomeric carbon of the donor sugar and the functional group of the sugar acceptor. This study found novel glycoside anomers without an anomeric carbon linkage of the sugar donor. A glycoside hydrolase (GH) enzyme, amylosucrase from Deinococcus geothermalis (DgAS), was evaluated to glycosylate ganoderic acid F (GAF), a lanostane triterpenoid from medicinal fungus Ganoderma lucidum, at different pH levels. The results showed that GAF was glycosylated by DgAS at acidic conditions pH 5 and pH 6, whereas the activity dramatically decreased to be undetectable at pH 7 or pH 8. The biotransformation product was purified by preparative high-performance liquid chromatography and identified as unusual α-glucosyl-(2→26)-GAF and β-glucosyl-(2→26)-GAF anomers by mass and nucleic magnetic resonance (NMR) spectroscopy. We further used DgAS to catalyze another six triterpenoids. Under the acidic conditions, two of six compounds, ganoderic acid A (GAA) and ganoderic acid G (GAG), could be converted to α–glucosyl-(2→26)-GAA and β–glucosyl-(2→26)-GAA anomers and α-glucosyl-(2→26)-GAG and β-glucosyl-(2→26)-GAG anomers, respectively. The glycosylation of triterpenoid aglycones was first confirmed to be converted via a GH enzyme, DgAS. The novel enzymatic glycosylation-formed glycoside anomers opens a new bioreaction in the pharmaceutical industry and in the biotechnology sector.

Molecular Structure of Flavonoids Determines the Efficacy of Glycosylation by Amylosucrase

“…DgAS demonstrates remarkable versatility in catalyzing glycosylation utilizing sucrose as a cost-effective glycosyl donor (Wu et al 2022). However, the enzyme-substrate interactions are governed by both structural complementarity and electronic compatibility, thereby in uencing the selectivity and e ciency of glycosylation (Goettig 2016).…”

Secretory expression of amylosucrase in Bacillus licheniformis through twin-arginine translocation pathway

“…Examples include carbohydrate-based dendritic nanoparticles (Putaux et al., 2006 ; Lee et al., 2022 ;) and baicalein-6-glucoside, which boasts enhanced stability, water solubility, and improved physiological properties (Kim et al., 2014 ), unusual quercetin diglucosides and isoquercitrin glucosides (Rha et al., 2020a , 2020b ) are among the compounds whose bioavailability can be enhanced through glycosylation by AS (Moon et al., 2021 ). This enzyme can also catalyze the formation of both α and β anomers of glycosides in triterpenoids from the medicinal fungus Ganoderma lucidum (Wu et al., 2022 ), and improve the solubility of puerarin (Ding et al., 2022 ).…”