Probing carbohydrate-lectin recognition in heterogeneous environments with monodisperse cyclodextrin-based glycoclusters

J Org Chem. 2012 Feb 3;77(3):1273-88. doi: 10.1021/jo201797b. Epub 2012 Jan 12.

Abstract

A series of β-cyclodextrin (βCD)-scaffolded glycoclusters exposing heterogeneous yet perfectly controlled displays of α-mannosyl (α-Man) and β-lactosyl (β-Lact) antennas were synthesized to probe the mutual influence of varying densities of the saccharide motifs in the binding properties toward different plant lectins. Enzyme-linked lectin assay (ELLA) data indicated that the presence of β-Lact residues reinforced binding of α-Man to the mannose-specific lectin concanavalin A (Con A) even though homogeneous β-Lact clusters are not recognized at all by this lectin, supporting the existence of synergic recognition mechanisms (heterocluster effect). Conversely, the presence of α-Man motifs in the heteroglycoclusters also resulted in a binding-enhancing effect of β-Lact toward peanut agglutinin (PNA), a lectin strongly binding multivalent lactosides but having no detectable affinity for α-mannopyranosides, for certain architectural arrangements. Two-site, sandwich-type ELLA data corroborated the higher lectin clustering efficiency of heterogeneous glycoclusters compared with homogeneous displays of the putative sugar ligand with identical valency. A turbidity assay was also consistent with the previous observations. Most revealingly, the lectin cross-linking ability of heterogeneous glycoclusters was sensitive to the presence of high concentrations of the non-ligand sugar, strongly suggesting that "mismatching" saccharide motifs may modulate carbohydrate-lectin specific recognition in a lectin-dependent manner when present in highly dense displays together with the "matching" ligand, a situation frequently encountered in biological systems.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carbohydrate Conformation
  • Lactose / chemistry
  • Mannose / chemistry
  • Models, Molecular
  • Plant Lectins / metabolism*
  • beta-Cyclodextrins / chemistry*
  • beta-Cyclodextrins / metabolism*

Substances

  • Plant Lectins
  • beta-Cyclodextrins
  • Lactose
  • Mannose