[Cell wall polysaccharide structure in the food protein yeast, Candida spec. H. I. Structure of alkali-stable mannoproteins]

Mannan structure analysis of the fragile Saccharomyces cerevisiae mutant VY1160

The fragile Saccharomyces cerevisiae mutant VY1160 has a cell-wall mannan with a lower molecular weight and a higher nitrogen content than the parental S288C strain. More mannobiose but less mannotriose and mannotetraose were found in O-glycosidically-bound oligosaccharides in the mutant. Acetolysis analysis of the alkali-stable mannan also showed a reduction of mannotetraose and an increase of the mannobiose fractions. Methylation analysis of total mannan, or side chains recovered after acetolysis, showed that in the mutant the amount of alpha(1-3)-linked mannose units prevailed over alpha(1-2)-linked residues.

[Polysaccharide structure of cell wall preparations from the food protein yeast Candida spec. H]

More than 27% of the cell wall are unstably bound components: Proteophosphomannan as a main polysaccharide of the cell wall, mannose and manno-oligosides which are bound to peptides or phosphate. 19% are glycosidically linked with a phosphate bridge or O-glycosidically (Ser/Thr) linked with the protein which is covalently bound to the cell wall. Besides mannose and glucose, manno-oligosides and gluco-oligosides are involved in this linkage. A preparation consisting of glucan and chitin remains after careful degradation. It contains (1,2)-, (1,3)- and (1,6)- linked glucose, (1, 2, 3)-, (1, 2, 6)- or (1, 3, 6)-glucose-branchpoints and (1,4)-linked N-acetylglucosamine.

[Cell wall polysaccharide structure in the food protein yeast, Candida spec. H. II. Characterization of phosphate binding to the mannan-protein-phosphate complex and identification of phosphodiester-bound mono- oligosaccharides]

The proteophosphomannan (PPM) obtained by extraction with citrate buffer, purification by the cetavlon method and gel filtration contains a high proportion of diesterified phosphate groups between the C-6 of a side chain mannose and another glycosidically bound carbohydrate. Mild acid hydrolysis cleaved the phosphate diester linkages to yield mono- and oligosaccharide fractions. Chemical analysis and 1H-NMR studies demonstrated the heterogeneity of the oligosaccharide fractions containing alpha(1,2)-, alpha(1,3)- and alpha(1,6)-linked manno-oligosaccharides. All repeated PPM preparations contained mono-, tri- and heptasaccharides as the phosphate bound main compounds. Galactose, arabinose, fucose, and rhamnose of the monosaccharide fraction and tetra-, penta- and hexasaccharides were not found in all preparations.