Schistosoma mansoni synthesizes novel biantennary Asn-linked oligosaccharides containing terminal beta-linked N-acetylgalactosamine.
This report describes the structure of novel complex-type Asn-linked oligosaccharides in glycoproteins synthesized by the human blood fluke, Schistosoma mansoni. Adult schistosome worm pairs (male and female) isolated from infected hamsters were metabolically radiolabelled with either [3H]glucosamine, [3H]mannose or [3H]galactose. The glycopeptides prepared by pronase digestion of the total glycoprotein fraction were isolated by affinity chromatography on columns of immobilized Concanavalin A (Con A) and Wisteria floribunda agglutinin (WFA). A subset of glycopeptides, designated IIb, that bound to both Con A and WFA was isolated. WFA has been shown to have affinity for oligosaccharides containing beta 1,4-linked N-acetylgalactosamine (GalNAc) at their non-reducing termini. Compositional analysis of IIb glycopeptides demonstrated that they contained N-acetylglucosamine (GlcNAc), GalNAc, mannose (Man) and fucose (Fuc), but no galactose (Gal) or N-acetylneuraminic acid (NeuAc). Methylation analyses and exoglycosidase digestions indicated that IIb glycopeptides were complex-type biantennary structures with branches containing the sequence GalNAc beta 1-4-[+/- Fuc alpha 1-3]GlcNAc beta 1-2Man alpha 1-R. The discovery of these unusual oligosaccharides synthesized by a human parasite, which appear to be similar to some newly discovered mammalian cell-derived oligosaccharides, may shed light on future studies related to the role oligosaccharides may play in host-parasite interactions.
Srivatsan
J
J
Department of Biochemistry, University of Georgia, Athens 30602.
Smith
D F
DF
Cummings
R D
RD
D000116:Acetylgalactosamine / Q000737:chemistry; D000818:Animals; D001216:Asparagine / Q000737:chemistry; D002240:Carbohydrate Sequence; D002850:Chromatography, Gel; D005260:Female; D006020:Glycopeptides / Q000096:biosynthesis / Q000737:chemistry; D006026:Glycoside Hydrolases; D008297:Male; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000096:biosynthesis* / Q000737:chemistry; D012550:Schistosoma mansoni / Q000378:metabolism*
D006020:Glycopeptides; D009844:Oligosaccharides; D001216:Asparagine; D006026:Glycoside Hydrolases; D000116:Acetylgalactosamine