Biosynthesis of Galactofuranose-containing Glycans in Filamentous Fungi

Abstract

Galactofuranose-containing glycans (Gal_f-glycans) are found in filamentous fungi, subphylum Pezizomycotina of Ascomycota. Although Gal_f-glycans have been broadly used as an indicator of pulmonary aspergillosis in clinical settings, and its importance in fungal cell growth is recognized, information pertaining to the galactofuranosyltransferase involved in the biosynthesis of Gal_f-glycans is sparse. In 2013, we identified and characterized the first galactofuranosyltransferase enzyme (GfsA) for the synthesis of Gal_f-glycans from a research model fungus, Aspergillus nidulans, and the human pathogen Aspergillus fumigatus. The enzyme belongs to the glycosyltransferase (GT) family 31. GfsA has the ability of transfer galactofuranose residues from the sugar donor UDP-galactofuranose to the non-reducing end of O-glycans in the Golgi apparatus. This review presents the process used to identify the enzyme, its enzymatic features, functions in the cell, and the biosynthesis of Gal_f-glycans in filamentous fungi.