Probing the stereoselectivity of OleD-catalyzed glycosylation of cardiotonic steroids

Abstract

The glycosyltransferase OleD variant as a catalyst for the glycosylation of four pairs of epimers of cardiotonic steroids (CTS) was assessed.

An Efficient Strategy for the Chemo‐Enzymatic Synthesis of Bufalin Glycosides with Improved Water Solubility and Inhibition against Na+, K+‐ATPase

“…It is noteworthy that synthesized 2-chloro-4-nitrophenol glucoside instead of UDPG was used as the sugar donor. [16] Compared to our previously reported sole chemical (total yield 10 % in four steps) [18] or enzymatic methods (30 %), [19] , the combined chemo-enzymatic strategy in this article greatly improved the yields of monoglycoside (68 %) and diglycoside (21 %) and decreased the experimental cost (90 %) because of the much higher price of UDPG. During the biosynthesis of bufalin glycosides, similar to the one-pot chemical reaction, [20] an one-pot enzymatical reaction incorporating the Loki-and ASP-glycosyltransferases was performed, which led to the direct synthesis of 3 and 4 without the need to isolate the intermediates.…”

The applicability of high‐speed counter‐current chromatography for preparative separation of biosynthesis products: Glycosylation products as example

“…ASP and Loki, two glycosyltransferases originated from bacteria, were cloned and expressed by E. coli based on literatures [33,35]. 2-Chloro-4-nitrophenyl-β-Dglucopyranoside was synthesized based on literatures in our laboratory [33].…”

“…Glycosylation is increasingly widespread for green and high efficiency. Targeting and water solubility could be enhanced, and side-effects, including toxicity, could be reduced through glycosylation [31][32][33][34][35]. Silybin B, originated from milk thistle (Silybum marianum, Asteraceae) known to the ancient Greeks as a medicinal plant already, is commonly used for treating liver disorders.…”

OcUGT1-Catalyzing Glycodiversification of Steroids through Glucosylation and Transglucosylation Actions

“…The hydroxyl group at C-3 position of steroids is the site attacked by most known SGTs [11,18]. However, OcUGT1 displayed no activity towards the hydroxyl group at C-3 position, which was evidenced by the fact that OcUGT1 did not react with steroids with C3-OH, such as cerberigenin (8), dehydroepiandrosterone (9), pregnenolone (10), 17α-hydroxypregnenolone (11), diosgenin (17), cholesterol (20), β-sitosterol (21), ergosterol (22), campesterol (23), and cholic acid (24).…”

“…The glycodiversification of natural products was thus dependent on the promiscuity of gylcosyltransferase. Although many steroidal glycosyltransferases (SGTs) had been isolated from varied species within the last few years [11,[16][17][18][19][20][21][22], most SGTs had not been fully explored for their glycodiversification potentials, including the multifunctional glycosyltransferase OcUGT1 [23]. In our previous reports, OcUGT1 was characterized to be a UDP-Glc-dependent glycosyltransferase with a catalytic flexibility, catalyzing diverse aglycons to form corresponding glycosides [23,24].…”