MALDI Imaging Assisted Discovery of a Di‐O‐glycosyltransferase from Platycodon grandiflorum Root

Abstract

A matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI MSI) assisted genome mining strategy was developed for the discovery of glycosyltransferase (GT) from the root of Platycodon grandiflorum. A di-O-glycosyltransferase PgGT1 was discovered and characterized that is capable of catalyzing platycoside E (PE) synthesis through the attachment of two β-1,6-linked glucosyl residues sequentially to the glucosyl residue at the C3 position of platycodin D (PD). Although UDP-glucose is the preferred sugar donor for PgGT1, it could also utilize UDP-xylose and UDP-N-acetylglucosamine as weak donors. Residues S273, E274, and H350 played important roles in stabilizing the glucose donor and positioning the glucose in the optimal orientation for the glycosylation reaction. This study clarified two key steps involved in the biosynthetic pathway of PE and could greatly contribute to improving its industrial biotransformation.

Genome-wide analysis of UDP-glycosyltransferases family and identification of UGT genes involved in drought stress of Platycodon grandiflorus

“…The phylogenetic tree was constructed using the 75 PgUGTs, 102 AtUGTs, 3 UGT genes in Zea mays ( Li et al., 2014 ) (GRMZM5G834303 in group P, GRMZM2G110511 and GRMZM2G168474 in group O) and PgGT1 in P. grandiflorus ( Tang et al., 2023 ) ( Figure 1 ). Based on the 14 conserved groups (A–N) found in Arabidopsis thaliana ( Li et al., 2001 ) and 3 UGT genes in Zea mays , the 75 PgUGTs were divided into 14 groups: none were placed in the F and K Groups, while 5 members were in Groups P and O, respectively.…”

Progress in Identification of UDP-Glycosyltransferases for Ginsenoside Biosynthesis

“…This approach led to the successful discovery of a di-O-glycosyltransferase, PgGT1, from Platycodon grandif lorum root. PgGT1 was found to catalyze a two-step glycosylation reaction on platycodin D to synthesize platycoside E. 93 Gene Cluster Analysis. Mounting evidence shows that genes for specific natural product biosynthetic pathways are colocalized in plant genomes within biosynthetic gene clusters (BGCs).…”

“…This approach led to the successful discovery of a di- O -glycosyltransferase, PgGT1, from Platycodon grandiflorum root. PgGT1 was found to catalyze a two-step glycosylation reaction on platycodin D to synthesize platycoside E …”

Development of an Efficient On-Tissue Epoxidation Reaction Mediated by Urea Hydrogen Peroxide for MALDI MS/MS Imaging of Lipid C═C Location Isomers

“…Matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI MSI) is a powerful tool for in situ chemical profiling from complex tissues due to its high throughput and sensitivity. − However, accurately determining the CC location of lipid isomers remains challenging, despite significant advancements in MALDI MSI in spatial lipidomics research . Conventional tandem MS with low-energy collision-induced dissociation (CID) fails to locate CC due to the higher collision energy required to break the CC bond.…”