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.
Institute of Biochemistry, Universität zu Köln, Federal Republic of Germany.
D
D
Balshüsemann
L
L
Jaenicke
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