A mannose-binding protein from the cell surface of flocculentSaccharomyces cerevisiae (NCIM 3528): its role in flocculation

✍ Scribed by Javadekar, V. S.; Sivaraman, H.; Sainkar, S. R.; Khan, M. I.

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 192 KB
• Volume: 16
• Category: Article
• ISSN: 0749-503X
• DOI: 10.1002/(sici)1097-0061(20000130)16:2<99::aid-yea500>3.0.co;2-6

✦ Synopsis

A cell surface lectin was isolated and puri®ed to homogeneity from the cell walls of a highly ¯occulent strain of Saccharomyces cerevisiae (NCIM 3528) by chromatography on DEAE-cellulose, phenyl Sepharose and Sephacryl S-300. It showed a molecular mass of 40 kDa on SDS±PAGE. It is an acidic protein with a pI of 4.0 and contains 44% hydrophobic amino acids. The N-terminal sequence up to 10 amino acid residues showed at least 70% homology with the predicted N-terminal sequence of the putative FLO1 as well as FLO5 gene products. The mannose-binding nature of the lectin was indicated by its high af®nity and speci®city towards the branched trisaccharide of mannose, a ligand which also inhibits the ¯occulation of yeast cells. Immuno¯uorescence studies con®rmed the presence of lectin on the yeast cell surface and lectin-speci®c IgGs prevented ¯occulation of the cells. This cell surface mannose-speci®c lectin probably plays an important role in ¯occulation, with the branched trimannoside on the cell wall being the apparent carbohydrate receptor. The N-terminal sequence data gives a primary indication that the lectin could be a product of one of the FLO genes.