Semirational Design of a UDP-Glycosyltransferase from for Efficient Biosynthesis of Rebaudioside M2.

Rebaudioside M2 (RebM2) is characterized as 13-[(2--β-d-glucopyranosyl-3--β-d-glucopyranosyl-β-d-glucopyranosyl)oxy] ent-kaur-16-en-19-oic acid-[(2--β-d-glucopyranosyl-6--β-d-glucopyranosyl-β-d-glucopyranosyl) ester], an isomer of rebaudioside M with a 1 → 6 sugar linkage. The product was found in the biotransformation of rebaudioside D (RebD) catalyzed by a glycosyltransferase from (UGT). Herein, guided by consensus engineering and molecular dynamics simulations, a variant UGT with enhanced activity and thermostability was obtained.

Engineering UDP-Glycosyltransferase UGTPg29 for the Efficient Synthesis of Ginsenoside Rg3 from Protopanaxadiol.

Rare ginsenosides Rg3 and Rh2, which exhibit diverse pharmacological effects, are derivatives of protopanaxadiol (PPD). UDP-glycosyltransferases, such as the M315F variant of Bs-YjiC (Bs-YjiCm) from Bacillus subtilis and UGTPg29 from Panax ginseng, can efficiently convert PPD into Rh2 and Rh2 into Rg3, respectively. In the present study, the N178I mutation of Bs-YjiCm was introduced, resulting in an increase in Rh2 production.

Identification of sucrose synthase from to favor biocatalytic glycosylation.

Sucrose synthase (SuSy, EC 2.4.1.

The rapid high-throughput screening of ω-transaminases via a colorimetric method using aliphatic α-diketones as amino acceptors.

ω-Transaminases (ω-TAs) are widely available for the production of chiral amines and unnatural amino acids. Herein, a rapid spectrophotometric method was developed for screening ω-TAs based on the colored products that can be generated from transamination reactions between aliphatic α-diketones and amino donors catalyzed by ω-TAs. The possible mechanism of the formation of the colored product was investigated according to LC-Q-TOF-MS analysis.

Screening UDP-Glycosyltransferases for Effectively Transforming Stevia Glycosides: Enzymatic Synthesis of Glucosylated Derivatives of Rubusoside.

Five plant-derived uridine diphosphate glycosyltransferases (UGTs) that catalyzed the glucosylation of stevia glycosides (SGs) were uncovered as the result of sequence mining considering the catalytic residues and conserved motifs of the known UGTs. Thereinto, UGT from with high activity toward rubusoside has been enzymatically characterized. The recombinant UGT was demonstrated to catalyze the β-1,6-glucosylation at C19 of rubusoside, producing a monoglucosyl derivative 13-[(-β-d-glucopyranosyl) oxy] ent-kaur-16-en-19-oic acid-[(6--β-d-glucopyranosyl-β-d-glucopyranosyl) ester], which was then submitted to a β-1,2-glucosylation by UGT, resulting in a diglucosyl derivative 13-[(-β-d-glucopyranosyl) oxy] ent-kaur-16-en-19-oic acid-[(2--β-d-glucopyranosyl-6--β-d-glucopyranosyl-β-d-glucopyranosyl) ester].

Bioconversion of Stevioside to Rebaudioside E Using Glycosyltransferase UGTSL2.

Rebaudioside E, one of the minor components of steviol glycosides, was first isolated and identified from Stevia rebaudiana in 1977. It is a high-intensity sweetener that tastes about 150-200 times sweeter than sucrose and is also a precursor for biosynthesis of rebaudioside D and rebaudioside M, the next-generation Stevia sweeteners. In this work, new unknown steviol glycosides were enzymatically synthesized from stevioside by coupling UDP-glucosyltransferase UGTSL2 from Solanum lycopersicum and sucrose synthase StSUS1 from Solanum tuberosum.