Mannose/tempo functionalized pamam dendrimers : their relative locations and components of affinity towards Concanavalin A

Abstract

Surface functionalized dendrimers are being used for several applications including the study of protein-carbohydrate interactions. Mannose-functionalized dendrimers with varying concentrations of saccharides on the dendrimer surface were synthesized. Spin labels (2,2,6,6-tetramethylpiperidine N-oxide) were incorporated onto the dendrimer's surface as well. Linebroadening effects in the EPR spectra of these compounds allowed us to determine the distance between spin labels (and thus between carbohydrates). The mannose-spin labeled functionalized dendrimers were further studied to determine effects of the spin label in hemagglutination inhibition assays. Affinity chromatography was employed to separate any mixture of compounds based on their affinity towards Concanavalin A, a mannose specific protein. The spin label on these compounds was used to study the relative conformations of the different compounds obtained from the affinity column. Synthesis of glucosamine funtionalized dendrimers was undertaken unsuccessfully. Had the synthesis been a success, TEMPO residues would have been attached to the amino sugar. EPR studies would have been used to determine the relative locations of the TEMPO labeled carbohydrates directly.