Glycosyltransferases, Chemistry of

Abstract

Glycosyltransferases (GTs) form glycosidic bonds by catalyzing the transfer of saccharides from a donor to a wide variety of acceptors. The donors used by GTs are sugars conjugated to nucleotides, phosphates, or lipid phosphates; whereas acceptors consist of carbohydrates, proteins, lipids, DNA, and numerous small molecules such as antibiotics, flavonols, steroids, and so on. Together, the products of these reactions comprise the most diverse and abundant class of natural compounds found in nature. Numerous GTs are needed to synthesize these compounds because the formation of each distinct glycosidic linkage requires a different enzyme. The abundance of these enzymes is emphasized by the fact that GTs constitute 1% of the genes in all genomes sequenced. They are ubiquitous in every kingdom of life and in all compartments of the cell. Currently, over 32,000 GT ORFs have been classified into 90 families on the basis of amino acid sequence similarity. The structures for 64 GTs have been determined to date and generally reveal conserved architectures of a GT‐A or GT‐B fold, although other folds have been observed and are predicted. These crystal structures, together with biochemical data, have provided insight into the catalytic mechanism. GTs generally exhibit strict regio/stereospecificity and transfer with either retention or inversion of configuration at the anomeric carbon of the donor sugar. The importance of characterizing the precise activity of these enzymes is exemplified by the many genetic disorders that have been linked to aberrant glycosylation.

Genetic and Biochemical Characterizations of Enzymes Involved in Streptococcus pneumoniae Serotype 2 Capsule Synthesis Demonstrate that Cps2T (WchF) Catalyzes the Committed Step by Addition of β1-4 Rhamnose, the Second Sugar Residue in the Repeat Unit

“…Donor substrates for glycosyltransferase reactions are usually activated in the form of nucleoside diphosphate sugars (6,10,11,36,56). dTDP rhamnose (dTDP-Rha) is one of the nucleotide-sugar donors utilized by S. pneumoniae capsular glycosyltransferases.…”

Surface and Adhesion Characteristics of Current and Next Generation Steel Packaging Materials

“…The water of hydration within the chromium structure is activated via thermal treatment, leading to the creation of a coordinated -OH network on the surface of the material for subsequent bonding within a chromium network. This olation process at the surface is followed by an oxolation process, with increased formation of Cr 2 O 3 species [15]. The imposition of vacuum results in lower initial chromium hydroxide levels on the surface and earlier transition of the chromium hydroxide to chromium oxide, Fig.…”

Glycosyltransferases and their Assays

“…Naturally occurring GT acceptor substrates belong to a wide range of different structural classes, including saccharides, proteins, peptides, lipids and secondary metabolites. [1][2][3][4][5] As glycosyl donors, GTs use either sugar nucleotides [23] such as UDP-galactose, GDP-mannose or CMP-sialic acid, or lipid-linked sugars such as dolicholphosphate mannose (Scheme 1 B). In both cases, the high-energy glycosyl-phosphate bond activates the donor sugar for the glycosyl transfer reaction.…”

“…Glycosyltransferases (GTs) are a class of enzymes that catalyse the transfer of a mono-or oligosaccharide from a glycosyl donor to a suitable acceptor [1][2][3][4][5] (Scheme 1 A). Such glycosylation reactions underpin many fundamental biological processes in all domains of life.…”