Preparation of fluorogenic glycopolymers having mannose moieties that can be used for determining the affinity of lectins by means of intermolecular FRET

Abstract

Quantitative evaluations of the binding affinities between glycopolymers and lectins in order to investigate the functionality of glycopolymers are of great importance. In this study, we developed fluorogenic glycopolymers that induce Förster resonance energy transfer (FRET) upon binding to lectins and we attempted directly to monitor the interaction followed by evaluation of the binding affinity on the basis of intermolecular FRET. Water-soluble glycopolymers with various polymer compositions containing mannose moieties as ligands for a lectin and dansyl moieties as fluorogenic chromophores for the FRET system were prepared, and the binding constant Ka (M−1) with concanavalin A (Con A; mannose-binding lectin) was estimated on the basis of the change in fluorescence intensity caused by FRET. Fluorescence measurements revealed intermolecular FRET between the fluorogenic glycopolymer and Con A, and the binding constants were estimated to be 0.398×106 ∼ 2.40×106 (M−1). The results suggested that this method can be applied to evaluation of the interaction when the binding of a glycopolymer to a lectin results in little fluorescence change.