Generic selectors
Exact matches only
Search in title
Search in content
Post Type Selectors

Author: jennbryant

Heparin Sulfate Arrays to Probe Binding Protein Specificity

Although hundreds of heparan sulfate binding proteins have been identified, and implicated in a myriad of physiological and pathological processes, very little information is known about ligand requirements for binding and mediating biological activities by these proteins. This difficulty results from a lack of technology for establishing structure-activity-relationships, which in turn is due to the structural complexity of natural HS and difficulties of preparing well-defined HS-oligosaccharides. To address this deficiency, we have developed a modular approach for the parallel combinatorial synthesis of HS oligosaccharides that utilizes a relatively small number of selectively protected disaccharide building blocks that can easily be converted into glycosyl donors and acceptors. These compounds can then be employed for the assembly of a wide range of HS-oligosaccharides.
The synthetic HS oligosaccharides are equipped with aminopropyl spacer, which made it possible to attach the compounds to microarray plates having reactive carboxylic acid moieties. The resulting HS oligosaccharide array is being further developed for high throughput screening to establish ligands for HS-binding proteins. In collaboration with several research groups, the synthetic HS-oligosaccharides are also employed as standards to develop mass spectrometry (MS)-based sequencing methods.

TSG-6 Link Module Displays Multiple modes of Glycosaminoglycan Binding

Link modules found in a number of cell surface proteins play important roles in stabilizing the extracellular matrix (ECM) by interacting with glycosaminoglycans (GAGs). However the specificity and geometry of these interactions is poorly defined. Driven by a collaborative project with the Tony Day lab of the University of Manchester, Younghee Park in the Prestegard group has applied forefront NMR methods to characterize binding modes of the link module of TSG-6, the secreted protein product of tumor necrosis factor-stimulated gene-6. A combination of chemical shift perturbation and paramagnetic relaxation enhancement, using defined and chemically modified oligomers of chondroitin sulfate, has identified two different binding sites (one strong and one weak). The second site appears to be formed after GAG induced dimerization of the Link module. The multiplicity of binding sites clearly can promote crosslinking and stabilization of the ECM.

Red and black ellipses on overlaid 1H-15N HSQC spectra, collected with increasing amounts of the hexameric chondroitin sulfate oligomer, show chemical shift patterns characteristic of fast and slow exchange. Fast and slow exchange residues are highlighted in red and blue respectively on the structure.

Back To Top