Structure of O-glycosidically linked oligosaccharides from glycoproteins of Trypanosoma cruzi CL-Brener strain: evidence for the presence of O-linkedsialyl-oligosaccharides

Glycoproteins on the cell surface of Trypanosoma cruzi are known to play im portant roles in the interaction of the parasite with the host cells. We pr eviously determined the structures of the O-glycan chains from the sialogly coproteins (mucin-like molecules) of the G- and Y-strains and observed sign ificant differences between them, We now report the structures of the sialy lated and nonsialylated O-linked oligosaccharides isolated from the cell su rface glycoproteins of the myotropic CL-Brener strain grown in the presence of fetal calf serum. The structures of the O-linked oligosaccharide aldito ls obtained by reductive beta -elimination of the sialoglycoprotein were de termined by a combination of methylation analysis, fast atom bombardment-ma ss spectrometry and nuclear magnetic resonance spectroscopy. The presence o f a beta -galactopyranose substituent on the N-acetylglucosamine 0-4 positi on shows that these O-linked oligosaccharides from CL-Brener strain belong to the same family as those isolated from mucins expressed by T. cruzi Y st rain, a reticulotropic strain. In addition, novel O-glycans, including alph a2-3 mono-sialylated species are described.