Microarray Analysis of Oligosaccharide-Mediated Multivalent Carbohydrate-Protein Interactions and Their Heterogeneity

Abstract

Carbohydrate-protein interactions (CPIs) are involved in a wide range of biological phenomena. Hence, the characterization and presentation of carbohydrate epitopes that closely mimic the natural environment is one of the long-term goals of glycosciences. Inspired by the multivalency, heterogeneity and nature of carbohydrate ligand-mediated interactions, we constructed a combinatorial library of mannose and galactose homo- and hetero-glycodendrons to study CPIs. Microarray analysis of these glycodendrons with a wide range of biologically important plant and animal lectins revealed that oligosaccharide structures and heterogeneity interact with each other to alter binding preferences.

Keywords: C-type lectin; heterogeneity; mannose; microarray; oligosaccharides.

Figure 1

Microarray analysis of M1 to M10 with plant and animal lectins. A) Bio-ConA, B) Bio-GNL, C) Bio-PNA, D) galectin-1, E) DC-SIGN-Fc, F) SIGNR3-Fc and G) MGL-1-Fc.

Figure 2

Principal component analysis of the fluorescence intensity of glycodendron binding with lectins. Inset: A screen plot of the percentage variance explained by each principal component.

Scheme 1

Synthesis of glycodendrons M1 to M4. a) NIS, TfOH, 6-azidohexan-1-ol; b) PPh₃, THF, water, Boc₂O; c) TFA (20%) in CH₂Cl₂; d) 6-azidohexan-1-ol, BF₃·Et₂O; PPh₃, THF, water, Boc₂O; e) 10′, Et₃N, CH₂Cl₂, RT; TEA in CH₂Cl₂; NaOMe, MeOH; f) 11′, Et₃N, CH₂Cl₂, RT; TEA in CH₂Cl₂; NaOMe, MeOH; g) 12′, Et₃N, CH₂Cl₂, RT; TEA in CH₂Cl₂; NaOMe, MeOH; h) 15′, Et₃N, CH₂Cl₂, RT; TEA in CH₂Cl₂; NaOMe, MeOH.

Scheme 2

Synthesis of glycodendrons M5 to M10. a) 10′, Et₃N, CH₂Cl₂, RT; b) 11′, Et₃N, CH₂Cl₂, RT; c) 12′, Et₃N, CH₂Cl₂, RT; d) 15′, Et₃N, CH₂Cl₂, RT; e) 15′, Et₃N, CH₂Cl₂, RT; TEA in CH₂Cl₂; NaOMe, MeOH; f) 10′, Et₃N, CH₂Cl₂, RT; TEA in CH₂Cl₂; NaOMe, MeOH; g) 11′, Et₃N, CH₂Cl₂, RT; TEA in CH₂Cl₂; NaOMe, MeOH; h) 12′, Et₃N, CH₂Cl₂, RT; TEA in CH₂Cl₂; NaOMe, MeOH.