Synthesis and Biological Role of Glycans

The biological functions of glycans span the range from those that appear to be relatively subtle, to those that are crucial for the growth, development, functioning, or survival of the organism that produces them. The biological functions of glycans can be divided into two broad groups: (1) the structural and modulatory properties of glycans and (2) the specific identification of glycans by other molecules most commonly, glycan-binding proteins (GBPs). The biological effects of changing glycosylation in numerous structures appear to be extremely variable and unpredictable. A particular glycan can have diverse functions in different tissues or at different intervals in development (organism-intrinsic functions) or in different environmental contexts (organism-extrinsic functions). Methods taken to recognize the biological roles of glycans comprise the inhibition of initial glycosylation, prevention of glycan chain elongation, alteration of glycan processing, genetic elimination of glycosylation sites, enzymatic or chemical deglycosylation of completed chains, and the study of naturally occurring genetic variants and mutants in glycosylation.