α-1,3-glucan

α-1,3-Glucan is a major polysaccharide in the cell walls of many fungi, including filamentous species like Aspergillus and yeasts like Schizosaccharomyces pombe, where it forms linear or near-linear chains of glucose residues primarily linked by α-1,3-glycosidic bonds, with minor α-1,4-linkages acting as spacers. It is synthesized by α-1,3-glucan synthases such as Ags1/AgsB and remodeled by enzymes like GH13-domain transglycosylases (e.g., Aah1/Aah3), contributing to the assembly of a mature α-glucan matrix essential for cell wall rigidity, morphology, and integrity. In pathogens like Histoplasma capsulatum and Aspergillus fumigatus, α-1,3-glucan masks immunogenic β-glucans, enabling immune evasion and promoting virulence during infection. Mutants lacking key synthases or remodelers show defects like cell clumping, lysis, reduced growth, and compensatory β-glucan increases, underscoring its structural role. While not a direct drug target, its presence influences fungal susceptibility to antifungals indirectly via cell wall dynamics, with content varying by species (e.g., 6-12% dry mass in Aspergillus).

Other names

α-glucan(1→3)-α-D-glucan1,3-α-glucan