Glycan microarray screening assay for glycosyltransferase specificities

Systemic Lectin-Glycan Interaction of Pathogenic Enteric Bacteria in the Gastrointestinal Tract

Microorganisms, such as bacteria, viruses, and fungi, and host cells, such as plants and animals, have carbohydrate chains and lectins that reciprocally recognize one another. In hosts, the defense system is activated upon non-self-pattern recognition of microbial pathogen-associated molecular patterns. These are present in Gram-negative and Gram-positive bacteria and fungi. Glycan-based PAMPs are bound to a class of lectins that are widely distributed among eukaryotes. The first step of bacterial infection in humans is the adhesion of the pathogen's lectin-like proteins to the outer membrane surfaces of host cells, which are composed of glycans. Microbes and hosts binding to each other specifically is of critical importance. The adhesion factors used between pathogens and hosts remain unknown; therefore, research is needed to identify these factors to prevent intestinal infection or treat it in its early stages. This review aims to present a vision for the prevention and treatment of infectious diseases by identifying the role of the host glycans in the immune response against pathogenic intestinal bacteria through studies on the lectin-glycan interaction.

Surface plasmon resonance as a tool to characterize lectin-carbohydrate interactions

Biosensors based on surface plasmon resonance (SPR) monitor changes in refractive index in the vicinity of a surface in a real-time manner, which allows rapid, label-free characterization of the interactions of various types of molecules, from quantitative measurements of binding kinetics, thermodynamics, and concentrations in complex samples to epitope analysis. This method is usually capable of analyzing affinities in the range of millimolar to picomolar and is sensitive (typically, the concentration range of the analyte is 0.1-100×Kd and the typical volumes needed are in the range of 50-150 μL). There are two major applications of SPR biosensors for the analysis of lectin-carbohydrate interactions: detailed characterization of the interaction (e.g., specificity, affinity, kinetics, stoichiometry) and screening of lectin and carbohydrate/glycoconjugate interactions for diagnosis, identification of endogenous ligands, or binding properties of interest. Care should be taken, since the interaction of lectin and carbohydrate on the solid phase is complicated by the nonhomogeneous conditions under which binding occurs. However, this may in fact mimic some biological conditions, such as those occurring in cell-cell interactions.