Constructing an Intensified UDP Recycling System for the Glycosylation of Natural Products by Phosphorylation of Byproduct Fructose
Yingying Wang, Qiuyan Sun, Yanfei Chi, Zhi‐Qiang Liu, Hu Liu, Chun Li, Xudong Feng
Abstract
UDP-glucosyltransferase can be coupled with sucrose synthase to construct a two-enzyme UDP (UDP-2E) recycling system for glucosylation of natural products with inexpensive sucrose as the consumed substrate. However, sucrose hydrolysis leads to the accumulation of fructose as a byproduct, which decreases the atom economy of sucrose and suppresses in situ UDP recycling. In this study, a polyphosphate-dependent glucokinase was demonstrated to convert fructose to fructose-6-phosphate independent of expensive ATP for the first time. Then the glucokinase was introduced into the UDP-2E recycling system to construct a modified three-enzyme UDP (UDP-3E) recycling system, which showed enhanced glucosylation efficiency of triterpenoids by fructose phosphorylation to accelerate sucrose hydrolysis and UDP recycling. Finally, by further introducing a phosphofructokinase into the UDP-3E recycling system, we transformed fructose-6-phosphate into fructose-1,6-diphosphate, demonstrating that the UDP-3E recycling system can be coupled with extra enzymes to obtain final products with high added-value without compromising the glycosylation efficiency.