Glycobiology of plants, bacteria, and viruses

This chapter focuses on the glycobiology of plants, bacteria, and viruses. The use of oligosaccharides derived from cell walls as signalling molecules in plants and the adoption of mammalian cell surface glycans as receptors for bacteria and viruses illustrate how glycans have been adapted to serve new functions during evolution. It is interesting to note that many of the non-mammalian lectins described in the chapter bind to mammalian glycan structures similar or identical to structures recognized by mammalian lectins. In other cases, sugar-binding activity seems to have arisen independently in the context of novel protein folds. Nevertheless, the themes of shallow, weak monosaccharide-binding sites that are extended and combined to achieve higher affinity is repeated in each branch of organisms and the sugar–protein interactions rely on many of the same types of hydrogen bonding and hydrophobic interactions.