Glycobiology & Glycochemistry

Discovery and Classification of Glycan Binding Proteins

Glycans can mediate a wide variety of biological roles by virtue of their mass, shape, charge, or other physical properties. However, many of their more specific biological roles are mediated via recognition by GBPs. Nature appears to have taken full advantage of the vast diversity of glycans expressed in organisms by evolving protein modules to recognize discrete glycans that mediate specific physiological or pathological processes. Excluding glycan-specific antibodies, GBPs broadly into two major groups such as lectins and glycosaminoglycan-binding proteins. Most lectins are members of families with defined “carbohydrate-recognition domains” (CRDs) that apparently evolved from shared ancestral genes, often retaining specific features of primary amino acid sequence or three-dimensional structure. Thus, new family members can be identified by searching protein sequence or structural databases. The natural ligands for most lectins are typically complex glycoconjugates that carry clustered arrays of the cognate carbohydrate or unique glycan structures, thus cooperating with clustered lectin-binding sites to generate high-avidity binding, which is further enhanced by mass transport effects (high local concentrations of ligands). Paulson group investigates the roles of glycan binding proteins that mediate cellular processes central to immune regulation and human disease. Their work includes at the interface of biology and chemistry to understand how the interaction of glycan binding proteins with their ligands mediates cell-cell interactions, endocytosis and cell signaling. Their multi-disciplinary approach is complemented by a diverse group of chemists, biochemists, cell biologists, and molecular biologists.