Characteristic differences in monosaccharide composition of glycoconjugates from opposite mating types of Chlamydomonas eugametos

Abstract

The monosaccharide composition of the isoagglutinins derived from the flagellar membranes of the opposite mating types of Chlamydomonas eugametos (mt+ and mt−) differ strikingly. Besides the common occurrence of L-arabinose, L-rhamnose, D-xylose, D-mannose, D-galactose, L-galactose, D-glucose, and 2-acetamido-2-deoxy-D-glucose, the mt+ isoagglutinin carbohydrate chains contain gulose, 4-O-methyxylose, a 2-O-methylpentose, and 3-O-methyl-D-galactose, whereas those of the mt− isoagglutinin contain 6-O-methyl-D-mannose and 3-O-methyl-L-glucose. Monosaccharide constituents were analysed by g.l.c. and g.l.c.-m.s. of trimethylsilylated methyl glycosides and alditol acetates. For the assignment of the absolute configurations using g.l.c., trimethylsilylated (−)-2-butyl glycosides were analysed. In view of the absolute specificity of the agglutination process displayed by the isoagglutinins of the sexually different mating types, the carbohydrate differences might be significant for the sexual interaction.