The oligosaccharides of the glycoprotein pheromone of Volvox carteri f. nagariensis Iyengar (Chlorophyceae).
The sexuality-inducing glycoprotein of Volvox carteri f. nagariensis was purified from supernatants of disintegrated sperm packets of the male strain IPS-22 and separated by reverse-phase HPLC into several isoforms which differ in the degree of O-glycosylation. Total chemical deglycosylation with trifluoromethanesulphonic acid yields the biologically inactive core protein of 22.5 kDa. This core protein possesses three putative binding sites for N-glycans which are clustered in the middle of the polypeptide chain. The N-glycosidically bound oligosaccharides were obtained by glycopeptidase F digestion and were shown by a combination of exoglycosidase digestion, gaschromatographic sugar analysis and two-dimensional HPLC separation to possess the following definite structures: (A) Man beta 1-4GlcNAc beta 1-4GlcNAc; (B) (Man alpha)3 Man beta 1-4GlcNAc beta 1-4GlcNAc Xyl beta; (C) (Man alpha)2 Man beta 1-4GlcNAc beta 1-4GlcNAc; (D) (Man)2Xyl(GlcNAc)2. Xyl beta Two of the three N-glycosidic binding sites carry one B and one D glycan. The A and C glycans are shared by the third N-glycosylation site. The O-glycosidic sugars, which make up 50% of the total carbohydrate, are short (up to three sugar residues) chains composed of Ara, Gal and Xyl and are exclusively bound to Thr residues.
Balshüsemann
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D
Institute of Biochemistry, Universität zu Köln, Federal Republic of Germany.
Jaenicke
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L
D002240:Carbohydrate Sequence; D000460:Chlorophyta / Q000032:analysis*; D002849:Chromatography, Gas; D004591:Electrophoresis, Polyacrylamide Gel / Q000379:methods; D006023:Glycoproteins / Q000302:isolation & purification*; D008969:Molecular Sequence Data; D009005:Monosaccharides; D009844:Oligosaccharides; D010455:Peptides; D010675:Pheromones / Q000302:isolation & purification*
D006023:Glycoproteins; D009005:Monosaccharides; D009844:Oligosaccharides; D010455:Peptides; D010675:Pheromones