High-affinity multivalent wheat germ agglutinin ligands by one-pot click reaction

Abstract

SummaryA series of six mono-, di-, and trivalent N,N’-diacetylchitobiose derivatives was conveniently prepared by employing a one-pot procedure for Cu(II)-catalyzed diazo transfer and Cu(I)-catalyzed azide–alkyne cycloaddition (CuAAC) starting from commercially available amines. These glycoclusters were probed for their binding potencies to the plant lectin wheat germ agglutinin (WGA) from Triticum vulgaris by an enzyme-linked lectin assay (ELLA) employing covalently immobilized N-acetylglucosamine (GlcNAc) as a reference ligand. IC50 values were in the low micromolar/high nanomolar range, depending on the linker between the two disaccharides. Binding enhancements β up to 1000 for the divalent ligands and 2800 for a trivalent WGA ligand, compared to N,N’-diacetylchitobiose as the corresponding monovalent ligand, were observed. Molecular modeling studies, in which the chitobiose moieties were fitted into crystallographically determined binding sites of WGA, correlate the binding enhancements of the multivalent ligands with their ability to bind to the protein in a chelating mode. The best WGA ligand is a trivalent cluster with an IC50 value of 220 nM. Calculated per mol of contained chitobiose, this is the best WGA ligand known so far.

In vitro evidence for the participation of Drosophila melanogaster sperm β‐N‐acetylglucosaminidases in the interactions with glycans carrying terminal N‐acetylglucosamine residues on the egg's envelopes

“…Initially, we have determined the presence of β‐ N ‐acetylglucosamine residues on the Drosophila eggshell. We used the WGA lectin that has an affinity for N ‐acetyl‐β‐D‐glucosaminyl residues and N ‐acetyl‐β‐D‐glucosamine oligomers (Beckmann, Möller, & Wittmann, ). Terminal β‐ N ‐acetylglucosamine residues are present on the surface of the chorion in mature oocytes, with a highly polarized localization on the micropyle and in the inner wall of the micropylar canal (Figure C, inset).…”

Biological Evaluation of Multivalent-Type N-Acetyl-D-Glucosamine (GlcNAc) Conjugates for Wheat Germ Agglutinin (WGA) by the Surface Plasmon Resonance (SPR) Method

“…The distance between binding sites of WGA is 13-14 Å (distances between anomeric oxygen's of two bound GlcNAc residues) [34,35] and the shortest distance between binding sites appears to be as small as 13 Å. For this reason WGA binds strongly to most multivalent analogs that can execute an assured degree of chelation and augment the binding with every valency [36]. The other two glycopolymers (1 and 2) are products after radical means of polymerization.…”

Multicomponent Syntheses based upon Copper‐Catalyzed Alkyne‐Azide Cycloaddition

“…[86] These glycoclusters were further screened for their binding potencies to the plant lectin wheat germ agglutinin (WGA) from Triticum vulgaris by an enzyme-linked lectin assay (ELLA) using covalently immobilized Nacetylglucosamine (GlcNAc) as a reference ligand. [86] These glycoclusters were further screened for their binding potencies to the plant lectin wheat germ agglutinin (WGA) from Triticum vulgaris by an enzyme-linked lectin assay (ELLA) using covalently immobilized Nacetylglucosamine (GlcNAc) as a reference ligand.…”

“…The convenience of this approach was also well established by the synthesis of the divalent glycoconjugates 36 and mono‐, di‐, and trivalent O ‐glycosidically linked N , N′ ‐diacetylchitobiose derivatives 37 86. These glycoclusters were further screened for their binding potencies to the plant lectin wheat germ agglutinin (WGA) from Triticum vulgaris by an enzyme‐linked lectin assay (ELLA) using covalently immobilized N ‐acetylglucosamine (GlcNAc) as a reference ligand.…”