Using structurally defined oligosaccharides to understand the interactions between proteins and heparan sulfate

Abstract

Heparan sulfate (HS) is widely present on the animal cell surface and in the extracellular matrix. HS achieves its biological functions by interacting with proteins to change proteins' conformation, oligomerization state and cellular location. The challenging question to study HS is how to dissect the relationship between the structures of HS and the biological activities. In the past several years, crucial techniques have been developed to overcome this challenge. A novel chemoenzymatic method to synthesize structurally defined HS oligosaccharides has offered a key access to this class of sulfated carbohydrate molecules. Recent rapid progress of HS microarray technology allows screening of the interaction of a target protein with a large number of HS oligosaccharides. The improved availability of HS oligosaccharides and HS microarray analysis will undoubtedly accelerate the investigation of the contribution of the specific sulfated carbohydrate structures of HS in a wide range of biological contexts.

Fig. 1

Structures of disaccharide repeating units of HS.

Fig. 2

Structures of the 3-O-sulfated octasaccharide and fondaparinux. The key disaccharide motifs that are responsible for binding to antithrombin are boxed.

Fig. 3

Images of HS-array analysis. Panel A shows schematic reactions for immobilization of an oligosaccharide on a functionalized array slide. Panel B shows the symbolic structures of 14 HS oligosaccharides that are immobilized on the array slide for microarray analysis. Panel C shows the schematic interaction of a fluorescently labeled antithrombin interacts with the oligosaccharides (1–7) on the array slide. Panel D shows the histogram of fluorescence intensity analysis when the array slide was hybridized with fluorescently labeled antithrombin. Here, the antithrombin was labeled with Alexa Fluo^® 488. The histogram data have been published in our previous publication [38].