AUTOHEPARIN · Automated Synthesis of Heparin and Chondroitin Libraries for the Preparation of Diverse Carbohydrate Arrays

While heparin, a glacosaminoglycan (GAG) has served as an anticoagulant for more than 60 years, the structure-activity relationship of heparin and chondroitin sulfate for specific interactions with proteins are still poorly understood. It has become evident that defined lengths and sequences or patterns are responsible for binding to a particular protein and modulating its biological activity. Determination of the structure-activity relationships of heparins and chondroitins creates an opportunity to modulate processes underlying viral entry, angiogenesis, kidney diseases and diseases of the central nervous system. The isolation of pure GAGs is extremely tedious and chemical synthesis is often the only means to access defined oligosaccharides. Currently available synthetic methods for the preparation of heparins and chondroitins are time consuming and lack generality. Therefore, it is still impossible to create large collections of GAG oligosaccharides for systematic studies of GAG-protein interactions. The overall goal of the project is the development of all aspects of automated GAG synthesis, the procurement of a large collection of heparin and chondroitin oligosaccharides of 2-10 sugars in length with a linker for ready attachment to microarray surfaces and other tools. These molecular tools will be employed to study the interaction of GAGs with growth factors, chemokines and other proteins. The specific aims include: 1) Synthesis of uronic acid and galactosamine building blocks; 2) Development of a new linker for automated GAG solid phase synthesis; 3) Construction of a new automated oligosaccharide synthesizer; 4) Development of methods for the automated assembly of heparin and chondroitin sulfate oligosaccharides; 5) Synthesis of a collection of defined heparin and chondroitin sulfate oligosaccharides; 6) Construction of synthetic GAG microarrays and SPR; 7) Preparation of GAG dendrimers and quantum dots.