Session: Current Topics in Biological Chemistry:

Many biological processes depend on carbohydrate recognitions to relay critical information and trigger crucial signaling events. Therefore, glycoscience research specifically concerning the carbohydrate-protein interactions can provide an abundant opportunity to discover molecular mechanisms of biological processes, potential therapeutic targets, and diagnostic mechanisms for various diseases. Developing useful tools to comprehensively elucidate the specificity of the carbohydrate-biding proteins (CBPs) and their functions. To achieve the goal of identifying the specificity of CBPs for particular glycan structures, a novel CBPs probing tool involving affinity photo-crosslinking was designed and its function was demonstrated. The aryl azide chain-end functionalized N-glycan polymer was first synthesized from free glycan via glycosylamine intermediate followed by acrylation and polymerization via cyanoxyl-mediated free radical polymerization (CMFRP) in one-pot fashion. Affinity-assisted photo-labeling capability of the aryl azide N-glycan polymers was demonstrated using beta-galactose-specific lectin from Arachis hypogaea (PNA) and glucose-specific lectin from Concanavalin A (ConA) followed by UV irradiation and confirmed by SDS-PAGE with silver staining. Overall, out of the three synthesized aryl azide chain-end functionalized polymeric probes expressing either glucose, galactose, or lactose, only the probes expressing lactose exhibited PNA specificity, which was consistent with expectation as they processed the beta-galactose moieties specifically known for PNA interactions. The results demonstrated our novel probes’ specific capability for binding and labeling lectins based on the lectin’s affinity for particular glycol groups on the glycopolymer, whose synthesis can be tailored to test the specificity of a lectin for different glycans. The aryl azide chain-end functionalized glycopolymers will be useful and effective biomimetic probes for specific protein labeling, functionality study and biomarker identification application both in vitro and in vivo.

Ka Keung Chan

Appearances