Structural analysis of water-soluble fractions obtained from Aspergillus fumigatus mycelium

Fractions were prepared from the water-soluble components of Aspergillus fumigatus mycelium either by lectin-affinity chromatography or salt precipitation. While they varied considerably in their amino-acid composition, each contained a preponderance of aspartic and glutamic acids. 13C-NMR spectroscopy of these fractions, compared with that of polysaccharide obtained by alkaline extraction, indicated the presence of glycoproteins, the polysaccharide components of which contained beta-D-Galf units that are part of structures chemically different from those obtained by alkali treatment. In two of the three fractions examined, gas-liquid chromatography--mass spectrometry showed marked differences in the contents of non-reducing end-units of alpha-D-Manp and beta-D-Galf. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis of the preparations revealed an array of components, which stained to differing extents with silver stain and with Coomassie Blue and many of which were bound by lectins with specificity for different sugars.