| To study the interactions between carbohydrate ligands and their receptors, the synthesis of several carbohydrate ligands was undertaken. Various Le x ligands for L-selectin, and galactose and mannose ligands for jacalin and Con A respectively, were constructed with functionalized linkers that allowed their incorporation into functionalized polymer backbones or functionalized gold surfaces. The binding affinity of these carbohydrate ligands for their receptors was then evaluated. Additionally, advances in the synthesis of UDP-Gal f ligands were achieved.; A new synthetic route to 3'-, 6-, and 3' ,6-disulfo Lex with an aminoethyl linker at the anomeric position was developed. Each of the monosaccharide building blocks is crystalline which enables large scale synthesis and facilitates the purification of intermediates. Additionally, a protecting group strategy that enables selective sulfation at the 3'-, 6-, and 3',6-positions of the Lex trisaccharide scaffold was developed. Once synthesized, the amine-functionalized trisaccharides were incorporated into functionalized polymers, which were generated using ROMP to study the effects of multivalency on Lex-L-selectin binding. Polymers substituted with 3 ',6-disulfo Lex were used in rolling assays to determine their ability to inhibit cell rolling. In addition, polymers substituted with 3'-sulfo Lex epitopes that contain a single ketone functional group at their terminus were immobilized on gold surfaces for analysis of selectin binding using surface plasmon resonance.; We also pursued the synthesis of Galf derivatives. Gal f residues are found in mycobacterial cell walls, and enzymes that mediate their incorporation are essential. To generate substrates for the enzymes involved in Galf incorporation, a new route for making Galf-alpha-phosphates was developed. In one step, the furanose ring and the alpha-phosphate linkage are simultaneously formed. This method affords the Galf-alpha-phosphate in the highest yield and selectivity known to date.; In the final chapter, we describe our first efforts to use SPR imaging to investigate protein-carbohydrate interactions in a high throughput manner. To this end, two carbohydrate ligands and a shikimic acid-derived glycomimetic were synthesized for immobilization. Using SPR imaging, the interactions of the carbohydrate-binding proteins Con A and jacalin with mannose and galactose-derivatived surfaces were monitored. |
