Structure of the glucan-binding sugar chain of Tip1p, a cell wall protein of Saccharomyces cerevisiae.
Tip1p is one of the major cell wall mannoproteins of Saccharomyces cerevisiae and is presumed to be synthesized as a glycosylphosphatidylinositol (GPI)-anchored form. We purified Tip1p from a glucanase extract of yeast cell walls and analyzed the sugar chain involved in the cell wall linkage. One mol of glucanase-extracted Tip1p contained 7.5 mol of glucose derived from glucan and 1 mol of ethanolamine, a component of the GPI anchor. One mol of the C-terminal peptide of Tip1p digested with Achromobacter protease I also contained 7.9 mol of glucose and 1 mol of ethanolamine. On the other hand, Tip1p contained no glucosamine, which is a component of the GPI anchor. The glucan-binding sugar chain of Tip1p was released by hydrazinolysis and isolated. This sugar chain contained ethanolamine with a free amino group and a glucose reducing end, but no mannose reducing end. Phosphodiesterase treatment eliminated the free amino group from this sugar chain, suggesting that a phosphodiester bond exists between the ethanolamine and the glucan remnant. These results indicate (1) the glucan-binding sugar chain of Tip1p is a GPI derivative, and (2) the GPI anchor is cleaved at the glycosyl moiety, and the resultant mannose reducing end is probably used to link Tip1p to cell wall glucan.
Fujii
T
T
National Research Institute of Brewing, 3-7-1 Kagamiyama, Higashihiroshima, Hiroshima 739-0046, Japan. fujii@nrib.go.jp
Shimoi
H
H
Iimura
Y
Y
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D002240:Carbohydrate Sequence; D002352:Carrier Proteins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D010450:Endopeptidases; D019856:Ethanolamine / Q000032:analysis; D005936:Glucans / Q000378:metabolism*; D006023:Glycoproteins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D006601:Hexoses / Q000032:analysis; D008562:Membrane Glycoproteins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D008969:Molecular Sequence Data; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins
D000596:Amino Acids; D002352:Carrier Proteins; D005936:Glucans; D006023:Glycoproteins; D006601:Hexoses; D008562:Membrane Glycoproteins; D029701:Saccharomyces cerevisiae Proteins; C070948:TIP1 protein, S cerevisiae; C025363:mannoproteins; D019856:Ethanolamine; D010450:Endopeptidases