Further structural studies of the carbohydrate moiety of the allergen Ag-54 (Cla h II) from the mould Cladosporium herbarum

Abstract The carbohydrate moiety of the glycoprotein allergen Ag-54, isolated from the mould Cladosporium herbarum , has been characterised partly, using acetolysis, methylation analysis, and n.m.r. spectroscopy. Ag-54 contained a highly branched galactoglucomannan and two branched mannogluco-oligosaccharide chains. The oligosaccharides contained terminal, (1→4)-, and (1→4,6)-linked α-Glc residues and terminal, (1→2)-, and some (1→3)-linked α-Man residues. The n.m.r. data indicated the galactoglucomannan to have a main chain made up of (1→6)-linked α-Man and (1→4)-linked α-Glc residues, with the latter attached to position 6 of α-Man residues. Oligosaccharides with (1→6)-linked β-Gal f and (1→2)-linked α-Man were attached to the main chain. Acetolysis of the galactoglucomannan yielded linear and branched oligosaccharides. The presence (1→2,3)-linked α-Man residues indicated either that other than (1→6) linkages were present in the main chain or that there was 2,3-branching in the side chains.