Isolation and characterization of a polypeptide absent from non-flocculent mutants of Saccharomyces cerevisiae [yeast genetics, SDS-gel electrophoresis, antibodies, column chromatography]
1978
Holmberg, S.
Alkaline cell extracts obtained from whole cells of a flocculent strain of Saccharomyces cerevisiae, containing the dominant gene for flocculence FL04, and a nonflocculent mutant (FL04, fsul) were analysed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The mutant lacked a low molecular weight (13,000) polypeptide present in the extract from the parent strain. This polypeptide difference was also observed when five other independently isolated non-flocculent mutants of the parent strain were analyzed. One of these five mutants was characterized genetically and also in this case was non-flocculence shown to be due to an unlinked suppressor mutation of FL04. This suppressor gene is designated fsu2. Analysis of petites with different flocculation phenotypes further extended the correlation between non-flocculence and the absence of the polypeptide. The polypeptide was isolated by gel filtration in the presence of sodium dodecyl sulfate followed by ion-exchange chromatography on DEAE-cellulose. By electrophoretic analysis the purity of the preparation was estimated to be 95 per cent. From amino acid analysis the polypeptide was calculated to consist of 121 residues with a molecular weight of 12,900 daltons. Differential extraction of proteins iodinated in situ by lactoperoxidase suggested an external location of the polypeptide.
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