Chemoenzymatic synthesis of glycosaminoglycans: Re-creating, re-modeling and re-designing nature's longest or most complex carbohydrate chains

Abstract

Glycosaminoglycans (GAGs) are complex polysaccharides composed of hexosamine-containing disaccharide repeating units. The three most studied classes of GAGs, heparin/heparan sulfate, hyaluronan and chondroitin/dermatan sulfate, are essential macromolecules. GAGs isolated from animal and microbial sources have been utilized therapeutically, but naturally occurring GAGs are extremely heterogeneous limiting further development of these agents. These molecules pose difficult targets to construct by classical organic syntheses due to the long chain lengths and complex patterns of modification by sulfation and epimerization. Chemoenzymatic synthesis, a process that employs exquisite enzyme catalysts and various defined precursors (e.g. uridine 5'-diphosphosphate-sugar donors, sulfate donors, acceptors and oxazoline precursors), promises to deliver homogeneous GAGs. This review covers both theoretical and practical issues of GAG oligosaccharide and polysaccharide preparation as single molecular entities and in library formats. Even at this early stage of technology development, nearly monodisperse GAGs can be made with either natural or artificial structures.

Pharmacology of Heparin and Related Drugs

“…To generate synthetic heparin with controllable structural and functional profiles, a different combined chemoenzymatic approach was also recently developed Chappell and Liu, 2013;DeAngelis et al, 2013). The enzymes of heparin/HS biosynthesis, expressed in E. coli or insect cells, may be used for postpolymerization transformations of a heparosan-like polymer made using bacterial enzymes.…”

Fibroblast Growth Factor-based Signaling through Synthetic Heparan Sulfate Blocks Copolymers Studied Using High Cell Density Three-dimensional Cell Printing

“…HS/HP polymerizing and modifying enzymes have been identified, cloned, expressed, and utilized for reactions in vitro (17)(18)(19)(20)(21)(22)(23). The backbones of these GAG chains can be efficiently and controllably synthesized in vitro using GAG synthases to add the monosaccharide units from UDP-sugar donors onto an acceptor or primer sugar (Fig.…”

“…The current study addresses this critical structural biology question by using a chemoenzymatic method (23) to synthesize several HS GAG chains having defined domain structures. These HS GAG chains were probed in a three-dimensional cellbased microarray using soluble FGFs and murine immortalized bone marrow (BaF3) cells developed by Ornitz and Itoh (38) and Ornitz and Leder (49) that express a single FGFR type and are completely devoid of HSPGs and FGFs; the assay output of cellular proliferation was measured to assess the ternary complex signaling process.…”

Uncovering the Catalytic Direction of Chondroitin AC Exolyase

“…Glycosaminoglycans (GAGs) 3 are long unbranched polysaccharides consisting of repeating disaccharide units that can be found in the connective tissues of animals (1,2). In terms of their structure, GAGs are composed of repeating disaccharide units containing a glucosamine (e.g.…”

“…In terms of their structure, GAGs are composed of repeating disaccharide units containing a glucosamine (e.g. galactosamine or glucosamine) and uronic acid, such as glucuronic acid (GlcA) or iduronic acid (IdoA) (2). Heparan sulfate (HS), chondroitin sulfate (CS), and hyaluronic acid (HA) are three of most extensively studied classes of GAGs (2).…”