Glucomannoproteins in the cell wall of Saccharomyces cerevisiae contain a novel type of carbohydrate side chain.
Mannoproteins in the walls of mnn9 cells of Saccharomyces cerevisiae were released by laminarinase, and purified by concanavalin A affinity chromatography and ion-exchange chromatography. Carbohydrate analysis revealed that they contained N-acetylglucosamine, mannose, and glucose. An antiserum raised against beta (1-6)-glucan reacted with four proteins with molecular masses of 66, 100, 155, and 220 kDa, respectively. Recognition by the antiserum was competitively inhibited by beta (1-6)-glucan, but not by beta (1-3)-glucan, mannan, or dextran (an alpha (1-6)-glucan). Mild periodate treatment of the wall proteins completely abolished recognition by the antiserum. Glucose-containing side chains were isolated and compared with N- and O-carbohydrate side chains. The glucose-containing side chains consisted of about equal amounts of glucose and mannose and some N-acetylglucosamine, and were larger than N-chains. They were, however, not extended N-chains, because after acetolysis, which preferentially cleaves (1-6)-linkages, their elution profiles differed strongly. A model is presented of how glucose-containing side chains might anchor mannoproteins into the glucan layer of the cell wall.
Institute of Molecular Cell Biology, University of Amsterdam, The Netherlands.
R C
RC
Montijn
J
J
van Rinsum
F A
FA
van Schagen
F M
FM
Klis
D000117:Acetylglucosamine / Q000032:analysis; D000908:Antibodies, Fungal / Q000276:immunology; D002240:Carbohydrate Sequence; D002473:Cell Wall / Q000737:chemistry* / Q000276:immunology; D005656:Fungal Proteins / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism; D005936:Glucans / Q000276:immunology; D005947:Glucose / Q000032:analysis; D006023:Glycoproteins / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism; D008358:Mannose / Q000032:analysis; D008361:Mannosidases / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000737:chemistry / Q000378:metabolism; D008969:Molecular Sequence Data; D012441:Saccharomyces cerevisiae / Q000737:chemistry* / Q000276:immunology; D043323:alpha-Mannosidase; D047071:beta-Glucans; D001617:beta-Glucosidase / Q000378:metabolism
D000908:Antibodies, Fungal; D005656:Fungal Proteins; D005936:Glucans; D006023:Glycoproteins; D008562:Membrane Glycoproteins; D047071:beta-Glucans; C025363:mannoproteins; C064197:beta-1,6-glucan; D008361:Mannosidases; D001617:beta-Glucosidase; D043323:alpha-Mannosidase; D005947:Glucose; D008358:Mannose; D000117:Acetylglucosamine