Cell wall glycopeptides of Candida albicans serotypes A and B

Abstract

Extraction of isolated cell walls of Candida albicans serotype A and B by anhydrous ethylenediamine yielded water-soluble and -insoluble glycopeptides. The water-soluble glycopeptides were separated into mannan peptides and glucan peptides by chromatography on Sephadex G-75. The ratio of proteins to carbohydrates of both types of water-soluble glycopeptides is higher in serotype A than in serotype B. In mannan peptides of both serotypes 12 amino acids were determined, with relatively large proportions of threonine and glutamic acid. The mannan peptides of serotype A exhibit greater proportions of aromatic amino acids, tyrosine and phenylalanine. In glucan peptides of both serotypes 10 amino acids were estimated, with relatively high contents of aspartic and glutamic acids. The alkali-induced β-elimination of mannan peptides with 0.1 M NaOH gave evidence for the presence of O- glycosidic linkages between disaccharides consisting of d-mannopyranose units and threonine. The O- glycosidic type of linkage was not estimated in water-soluble glucan peptides. Periodate oxidation of the mannan component of mannan peptides showed that the mannan is a highly branched polysaccharide with higher average chain length in serotype A than in serotype B. The glucan part of the insoluble glucan peptides possesses predominantly the 1 → 3 linkages configuration.