Biosynthesis of Fungal and Yeast Glycans

Fungi produce a remarkable range of glycans and glycoconjugates. The pathways responsible for the synthesis of these structures differ greatly from those of prokaryotic organisms because of the distinct structures formed and to accommodate the topology of eukaryotic organelles. Fungal pathways leading to the formation of some glycans, such as those linked to protein, present variations on general eukaryotic themes, while pathways forming other structures, such as the cell wall, are unique to these organisms. This chapter presents an overview of fungal glycan biosynthesis, beginning with the precursor molecules that contribute to biosynthetic pathways and proceeding to individual classes of glycoconjugates. The most detailed studies of glycan and glycoconjugate biosynthesis in fungi have been performed in the model organism Saccharomyces cerevisiae. The chapter also describes the differences in glycosylation and biosynthetic machinery between S. cerevisiae and other fungal species and mentions variations between fungi and higher eukaryotes. The unique aspects of fungal biosynthesis may present opportunities for the development of selective antifungal chemotherapies.