Glycosyltransferases (GTs) catalyze the transfer of a sugar residue of an activated sugar donor to an acceptor molecule. Many families 1 GTs utilize an uridine diphosphate (UDP) activated sugar as donor in the glycosylation reaction, and most of these belong to a group of GTs referred to as the UGTs. The relationship between the degree of amino acid sequence identity and substrate specificity of the plant UGTs is highly complicated, and the prediction of substrate specificity based on phylogenetic analyses need to be improved by more biochemical characterization. This review summarizes the three dimensional structures of plant UGTs published in the Protein Data Bank (PDB), including the detailed substrate interactions with the sugar and receptor binding pockets and mutational analyses of some critical amino acids. It will be helpful for biochemical characterization the substrate specificity of the individual UGT, and lay the foundation for the enzymatic and genetic manipulation of plant UGTs in the future.
Amino Acid Sequence ; Glycosylation ; Glycosyltransferases ; chemistry ; Phylogeny ; Plant Proteins ; chemistry ; Plants ; enzymology ; Protein Structure, Tertiary ; Substrate Specificity ; Uridine Diphosphate ; chemistry

The chalcone synthase (CHS) superfamily of the type III polyketide synthases (PKSs) generates backbones of a variety of plant secondary metabolites. Benzalacetone synthase (BAS) catalyzes a condensation reaction of decarboxylation between the substrates of 4-coumaric coenzyme A and malonyl coenzyme A to generate benzylidene acetone, whose derivatives are series of compounds with various biological activities. A BAS gene Pcpks2 and a bifunctional CHS/BAS PcPKSI were isolated from medicinal plant P. cuspidatum. Crystallographic and structure-based mutagenesis studies indicate that the functional diversity of the CHS-superfamily enzymes is principally derived from small modifications of the active site architecture. In order to obtain an understanding of the biosynthesis of polyketides in P. cuspidatum, which has been poorly described, as well as of its activation mechanism, PcPKS2 was overexpressed in Escherichia coli as a C-terminally poly-His-tagged fusion protein, purified to homogeneity and crystallized, which is helpful for the clarification of the catalytic mechanism of the enzyme and lays the foundation for its genetic engineering manipulation.
Butanones ; Catalytic Domain ; Crystallization ; Fallopia japonica ; enzymology ; Polyketide Synthases ; genetics ; metabolism

Objective:The therapeutic effect of less polar ginsenosides on rats with rheumatoid arthritis was studied, and the metabolic pathway that produce anti-inflammatory effect of less polar ginsenosides was identified.Methods:Rats were randomly divided into the control group, the model group, methotrexate treatment group, and high dose, medium dose, and low dose less polar ginsenosides groups. After 30 days of oral administration, less polar ginsenosides reduced the disease activity significantly in rats with rheumatoid arthritis. Blood and ankle synovial tissue metabolisms were measured by ultra performance liquid chromatography (UPLC) tandem mass spectrometry (MS) to explore the mechanism of less polar ginsenosides.The resulting data were subjected to principal component analysis and orthogonal partial least squares discriminant analysis(OPLS-DA).Results:Compared with the model group, erythrocyte sedimentation rate and RF decreased significantly in the high dose of less polar ginsenosides ( P<0.01). Metabolomics showed that R2X and R2Y of serum OPLS-DA were 0.626 and 0.904 respectively. The R2X and R2Y of synovial OPLS-DA were 0.429 and 0.689 respectively. Major differential metabolites were identified in the model group of rats, including arachidonic acid, valine, linoleic acid, and guanine nucleoside, etc. The main differential metabolites were identified in rats in the high dose group of less polar ginsenosides, including linoleic acid, betaine, eicosapentaenoic acid, alanine, methionine sulfoxide, isoleucine, etc. Conclusion:The metabolic spectrum has shown that inflammation is associated with linoleic acid metabolism, valine, leucine and isoleucine degradation, arachidonic acid metabolism. Less polar ginsenosides regulatethe linolenic acid metabolism, methionine metabolism and glucose alanine cycle.

Salidroside, as one of the main active ingredients of Rhodiala plant, has the effects of anti-hypoxia, anti-radiation, anti-fatigue, anti-tumor, hypoglycemia and improving immunity. With the increasing demand for salidroside and the decreasing of plant resources, microbial production of salidroside has attracted much attention due to its advantages of short period and easy controlling. At present, microbial production of salidroside is still at the basic research stage. In order to make it easier for researchers to understand the advances of microbial synthesis of salidroside, the biosynthesis pathways, uridine diphosphate glucosyltransferases, wild strain/natural enzymes and engineered strain/recombinant enzymes were reviewed.
Biosynthetic Pathways ; Glucosides ; metabolism ; Phenols ; metabolism

Raspberry ketones have important therapeutic properties such as anti-influenza and prevention of diabetes. In order to obtain raspberry ketone from Chlamydomonas reinhardtii, two enzymes catalyzing the last two steps of raspberry ketone synthesis, i.e. 4-coumaryl-CoA ligase (4CL) and polyketide synthase (PKS1), were fused using a glycine-serine-glycine (GSG) tripeptide linker to construct an expression vector pChla-4CL-PKS1. The fusion gene 4CL-PKS1 driven by a PSAD promoter was transformed into a wild-type (CC125) and a cell wall-deficient C. reinhardtii (CC425) by electroporation. The results showed the recombinant C. reinhardtii strain CC125 and CC425 with 4CL-PKS1 produced raspberry ketone at a level of 6.7 μg/g (fresh weight) and 5.9 μg/g (fresh weight), respectively, both were higher than that of the native raspberry ketone producing plants (2-4 μg/g).
Acyl Coenzyme A ; Butanones ; Chlamydomonas reinhardtii/genetics* ; Ligases ; Polyketide Synthases