Characterization of dolichol monophosphate- and dolichol diphosphate-linked saccharides in trypanosomatid flagellates

Abstract

Dolichol-P- and dolichol-P-P-linked saccharides were isolated from several trypanosomatid flagellates incubated with [U- 14C]glucose. Formation of Glc-P-dolichol and Man-P-dolichol was observed in Herpetomonas muscarum and Leishmania adleri, whereas only the latter derivative was synthesized in Trypanosoma dionisii and Leptomonas samueli. The main and largest dolichol-P-P-linked oligosaccharide formed in Trypanosoma conorhini, T. dionisii, L. samueli, Herpetomonas samuelpessoai and H. muscarum appeared to be Man 9GlcNAc 2, whereas in Blastocrithidia culicis it was Man 6GlcNAc 2. In L. adleri there were two main oligosaccharides linked to dolichol-P-P, Man 6GlcNAc 2 and Man 5GlcNAc 2. The structures of the oligosaccharides were identical with those of the intermediates in the formation of Glc 3Man 9GlcNAc 2-P-P-dolichol in higher eucaryotes. It was concluded that similarly to Trypanosoma cruzi, Crithidia fasciculata and Leishmania mexicana, no glucosylated derivatives of dolichol-P-P were formed in the additional seven trypanosomatids studied here. The results obtained suggest that the defective step could be in some cases the formation of Glc-P-dolichol and in others, the transfer of glucose residues from the latter compound to dolichol-P-P-linked oligosaccharides.