Use of a Promiscuous Glycosyltransferase from Bacillus subtilis 168 for the Enzymatic Synthesis of Novel Protopanaxatriol-Type Ginsenosides

Abstract

Ginsenosides are the principal bioactive ingredients of Panax ginseng and possess diverse notable pharmacological activities. UDP-glycosyltransferase (UGT)-mediated glycosylation of the C6-OH and C20-OH of protopanaxatriol (PPT) is the prominent biological modification that contributes to the immense structural and functional diversity of PPT-type ginsenosides. In this study, the glycosylation of PPT and PPT-type ginsenosides was achieved using a promiscuous glycosyltransferase (Bs-YjiC) from Bacillus subtilis 168. PPT was selected as the probe for the in vitro glycodiversification of PPT-type ginsenosides using diverse UDP-sugars as sugar donors. Structural analysis of the newly biosynthesized products demonstrated that Bs-YjiC can transfer a glucosyl moiety to the free C3-OH, C6-OH, and C12-OH of PPT. Five PPT-type ginsenosides were biosynthesized, including ginsenoside Rh1 and four unnatural ginsenosides. The present study suggests flexible microbial UGTs play an important role in the enzymatic synthesis of novel ginsenosides.

Enzyme-Catalyzed Glycosylation of Curcumin and Its Analogues by Glycosyltransferases from Bacillus subtilis ATCC 6633

“…The pharmacological properties of these biosynthesized glucosides should be further studied, and deep structural analysis of BsGT1 and BsGT2 should also be undertaken to elucidate the difference in catalytic properties. Furthermore, this method could be applied to boost the aqueous solubility and bioavailability of other active hydrophobic compounds, and it would be of great interest to introduce the two GTs into glucoside-producing chassis cells to accelerate the production of natural or natural-like active glucosides via metabolic engineering [17].…”

“…Studies of microbial GTs have attracted increasing interest and achieved tremendous progress in the enzymatic O-glycosylation of both natural and unnatural compounds, such as ginsenosides [17,20,23,24], antibiotics [25,26], glycopeptides [27,28], flavonoids [18,[29][30][31], and other polyphenols [19,32]. In this study, compared with YjiC from Bacillus licheniformis DSM 13, CaUGT2 from Catharanthus roseus, and UGT76G1 from Stevia rebaudiana catalyzing curcumin to diglucoside and monoglucoside [33][34][35], BsGT1 and BsGT2 could catalyze curcumin and its two analogues to only their monoglucosides, which indicate that the two GTs are highly selective to the single phenolic hydroxyl group of such compounds.…”

“…Therefore, the strategy of enzymatic synthesis of NP glucosides by GTs has been to develop a means to obtain glycosylated small molecules. For example, Bs-YjiC (a GT from Bacillus subtilis 168) could transfer a glucosyl moiety to three particular free OHs of protopanaxatriol, forming its glucoside derivatives [17], and a UGT from Bacillus licheniformis was elucidated for the glycosylation of phloretin to produce five phloretin glucosides [18]. Moreover, it is encouraging that a fungal GT from Mucor hiemalis exerts the substrate promiscuity of the 72 structurally diverse drug-like natural products [19].…”

Biocatalytic Synthesis of a Novel Bioactive Ginsenoside Using UDP-Glycosyltransferase from Bacillus subtilis 168

“…Over 140 ginsenosides have been isolated from diverse Panax species [10]. These naturally occurring products are mainly grouped into protopanaxadiol-type (PPD) and protopanaxatriol-type (PPT) according to the structure of the aglycone skeleton [11].…”

“…Bs-YjiC from Bacillus subtilis 168 is a flexible and effective UGT toward a numerous number of structurally diverse compounds [21,22]. Bs-YjiC could glucosylate the C3, C6, and C12 hydroxyl groups of PPT to synthesize unnatural ginsenosides [10]. Bs-YjiC could also catalyze a continuous two-step glucosylation of the C3 and C12 hydroxyl groups of PPD to synthesize ginsenoside Rh2 and an unnatural ginsenoside F12 [23].…”