Assessing Carbohydrate–Carbohydrate Interactions by NMR Spectroscopy: The Trisaccharide Epitope from the Marine Sponge Microciona prolifera

Abstract

WEAK RECOGNITION PROCESSES: Weak calcium-mediated carbohydrate-carbohydrate interactions have been detected by DOSY and TRNOESY NMR methods by employing a gold glyconanoparticle as a multivalent system. In addition, 3D models of trisaccharide-Ca(II)-trisaccharide complexes based on results from molecular dynamics simulations are proposed. Diffusion-ordered NMR spectroscopy (DOSY-NMR) and TR-NOESY-NMR experiments are used to detect ligand binding to macromolecular receptors. These techniques have been applied to detect weak carbohydrate-carbohydrate self-recognition in solution, making use of sugar-decorated gold nanoparticles as the "macromolecule" and the same carbohydrate as the ligand. Changes in the diffusion coefficient of the free carbohydrate in the presence of the glyconanoparticle (only with Ca(II) ions in the sample solution), as well as changes in the sign of the sugar NOE peaks--positive for the free sugar (in the presence or absence of Ca(II)) and negative for the sugar only in the simultaneous presence of the glyconanoparticle and Ca(II) ions--have been taken as proof of weak Ca(II)-mediated carbohydrate-carbohydrate interactions in solution. Although different methods such as SPR, TEM, and AFM have been used in the past to detect carbohydrate-carbohydrate interactions with the aid of gold nanoparticles and gold selfassembled monolayers, they are restricted to high-affinity ranges. The methods used in this study allow expansion of the number of techniques to tackle this relevant biological problem, also for approaching ligand-receptor interactions below the high-affinity range. Additionally, 3D models of trisaccharide-Ca(II)-trisaccharide complexes based on results from molecular dynamics simulations are proposed.

Protein-Carbohydrate Interactions Studied by NMR: From Molecular Recognition to Drug Design

“…This research extended the employment of DOSY methods to detect carbohydrate interactions besides those frequently encountered in the cyclodextrin field and to monitor molecular size in natural and artificial carbohydrate polymers and glycodendrimers. [47]…”

Model System for Cell Adhesion Mediated by Weak Carbohydrate–Carbohydrate Interactions

“…Two oligosaccharide epitopes, the pyruvated trisaccharide β-D-Gal(4,6-( R )-Pyr)-(1→4)-β-D-GlcNAc(1→3)-α-L-Fuc and the sulfated disaccharide β-D-GlcNAc(3S)-(1→3)-α-L-Fuc have been shown to be essential for cell-cell interactions in M. prolifera . 6,7 …”

The complexity of glycoprotein-derived glycans

“…A number of techniques including SPR, NMR and X-ray crystallography are available to study aspects of the interaction of the glycan. 105,106) Although for biological functions the attention is mainly focused on intermolecular interactions, also the intramolecular interactions should be taken into account. The latter interaction may affect the protein-folding and the three-dimensional structure of the glycoprotein.…”