Glycans serve a critical role in cell-cell communication and function through their interaction with other biomolecules, such as proteins. Glycan-biomolecule interaction has several unique features, including high specificity, low avidity, multi-valency, high on-rates/off-rates of binding and responsiveness to environmental changes.
Biomolecular Interaction and The Interactome
Glycan microarrays are being constructed containing glycosaminoglycans having different sequences at each spatially addressable location. These glycan chains are either first, purified, structural characterized and then immobilized or are synthesized at site. By probing such glycan microarrays with proteins from a given cell, tissue or organism the interactome can be established.
The thermodynamic (∆H) and kinetic (kon/koff) properties of proteincarbohydrate interactions are important parameters to understand binding. The ∆H, ∆S and stoichiometry of binding can be measured using isothermal titration calorimetry (ITC) while the kon/koff , Kassoc, Kdissoc, Keq can be conveniently measured using surface plasmon resonance (SPR). SPR and ITC can also provide information on conformation changes in binding, cooperativity, ionic vs.
The atomic contacts between glycosaminoglycan and its binding protein are determined by single crystal X-ray crystallography. The first high-resolution co-crystal