Divergent Synthesis of Heparan Sulfate Oligosaccharides

Abstract

Heparan sulfates are implicated in a wide range of biological processes. A major challenge in deciphering their structure and activity relationship is the synthetic difficulties to access diverse heparan sulfate oligosaccharides with well-defined sulfation patterns. In order to expedite the synthesis, a divergent synthetic strategy was developed. By integrating chemical synthesis and two types of O-sulfo transferases, seven different hexasaccharides were obtained from a single hexasaccharide precursor. This approach combined the flexibility of chemical synthesis with the selectivity of enzyme-catalyzed sulfations, thus simplifying the overall synthetic operations. In an attempt to establish structure activity relationships of heparan sulfate binding with its receptor, the synthesized oligosaccharides were incorporated onto a glycan microarray, and their bindings with a growth factor FGF-2 were examined. The unique combination of chemical and enzymatic approaches expanded the capability of oligosaccharide synthesis. In addition, the well-defined heparan sulfate structures helped shine light on the fine substrate specificities of biosynthetic enzymes and confirm the potential sequence of enzymatic reactions in biosynthesis.

Salt-free fractionation of complex isomeric mixtures of glycosaminoglycan oligosaccharides compatible with ESI-MS and microarray analysis

“…Previous work by Zaia and coworkers have shown that amide-HILIC retention time is dominated by acetyl and sulfate composition for Hp/HS oligosaccharides of a given size 39 , indicating that FGF2 binding increases as sulfate content increases. This is consistent with previous microarray results using synthetic oligosaccharides that showed that FGF2 binds all highly sulfated GAG tetrasaccharides well, while intermediately sulfated structures showed a clear structure-function relationship 40 , and is consistent with other FGF2 binding structure-function studies showing preference for high sulfation and indicating the importance of 2- O -sulfation and N -sulfation to FGF2 binding 41-44 .…”

Synthetic Oligosaccharide Libraries and Microarray Technology: A Powerful Combination for the Success of Current Glycosaminoglycan Interactomics

“…Subsequent studies greatly expanded the repertoire of GAG oligosaccharides available in a glycoarray. For instance, the groups of Xuefei Huang and Jian Liu collaborated to synthesize several GAG oligosaccharides by assembling the GAG carbohydrate backbone using de no synthesis and then sulfating them using sulfotransferases (Figure ) . This method allowed them to create nine Hp hexasaccharides with differing sulfation patterns for microarray study.…”

“…For instance, the groups of Xuefei Huang and Jian Liu collabo-rated to synthesize severalG AG oligosaccharidesb ya ssembling the GAG carbohydrate backboneu sing de no synthesis and then sulfating them using sulfotransferases (Figure 2). [38] This method allowed them to create nine Hp hexasaccharides with differing sulfation patterns for microarrays tudy.T he Liu group went on to create am icroarray of fourteen HS heptasaccharideu sing only chemoenzymatic synthesis in as eparate study. [24ai] In that study,t he authors also attempted toq uantify the density of oligosaccharide on the surface by digesting the immobilized oligosaccharides with Hp lyases andq uantifying the released disaccahrides.T heir conclusion was that immobilization efficiency ranged from 1t o1 0%.R ecently,t he most ex-tensiveG AG microarray created to date has just been published by Boons and colleagues.…”

Programmable one-pot synthesis of heparin pentasaccharides enabling access to regiodefined sulfate derivatives

“…The chemical synthesis of H/HS oligosaccharides is challenging due to the laborious and repetitive steps of protection, uncontrolled stereoselective glycosylation, deprotection, and multiple purification processes, which give low efficiencies and low yields. 15 However, over the years, chemical and chemo-enzymatic 16 methodologies have been reported for the synthesis of heparin-like oligosaccharides, 17 – 20 and the heparin-based drugs fondaparinux 21 and idraparinux. 22 To overcome the disadvantages of multi-step oligosaccharide synthesis, we have developed a computer database, OptiMer, to store the relative reactivity values (RRVs) of many glycosyl donors/acceptors.…”