C-Glycosides are important natural products with various bioactivities.In plant biosynthetic pathways,the C-glycosylation step is usually catalyzed by C-glycosyltransferases(CGTs),and most of them prefer to accept uri...C-Glycosides are important natural products with various bioactivities.In plant biosynthetic pathways,the C-glycosylation step is usually catalyzed by C-glycosyltransferases(CGTs),and most of them prefer to accept uridine 5’-diphosphate glucose(UDP-Glc)as sugar donor.No CGTs favoring UDP-rhamnose(UDP-Rha)as sugar donor has been reported,thus far.Herein,we report the first selective C-rhamnosyltransferase VtCGTc from the medicinal plant Viola tricolor.VtCGTc could efficiently catalyze C-rhamnosylation of 2-hydroxynaringenin 3-C-glucoside,and exhibited high selectivity towards UDP-Rha.Mechanisms for the sugar donor selectivity of VtCGTc were investigated by molecular dynamics(MD)simulations and molecular mechanics with generalized Born and surface area solvation(MM/GBSA)binding free energy calculations.Val144 played a vital role in recognizing UDP-Rha,and the V144T mutant could efficiently utilize UDP-Glc.This work provides a new and efficient approach to prepare flavonoid C-rhamnosides such as violanthin and iso-violanthin.展开更多
基金supported by National Natural Science Foundation of China(Grants No.81725023 to Min Ye and 82003614 to Yang Yi)China National Postdoctoral Program for Innovation Talents(No.BX20220022 to Zi-Long Wang).the Swedish National Infrastructure for Computing(SNIC)at the National Supercomputer Center(SNIC2022-3-34)at Link?ping University(Sweden)。
文摘C-Glycosides are important natural products with various bioactivities.In plant biosynthetic pathways,the C-glycosylation step is usually catalyzed by C-glycosyltransferases(CGTs),and most of them prefer to accept uridine 5’-diphosphate glucose(UDP-Glc)as sugar donor.No CGTs favoring UDP-rhamnose(UDP-Rha)as sugar donor has been reported,thus far.Herein,we report the first selective C-rhamnosyltransferase VtCGTc from the medicinal plant Viola tricolor.VtCGTc could efficiently catalyze C-rhamnosylation of 2-hydroxynaringenin 3-C-glucoside,and exhibited high selectivity towards UDP-Rha.Mechanisms for the sugar donor selectivity of VtCGTc were investigated by molecular dynamics(MD)simulations and molecular mechanics with generalized Born and surface area solvation(MM/GBSA)binding free energy calculations.Val144 played a vital role in recognizing UDP-Rha,and the V144T mutant could efficiently utilize UDP-Glc.This work provides a new and efficient approach to prepare flavonoid C-rhamnosides such as violanthin and iso-violanthin.
