A UNIQUE MULTIFUCOSYLATED -3GALNAC-BETA-1-]4GLCNAC-BETA-1-]3GAL-ALPHA-1- MOTIF CONSTITUTES THE REPEATING UNIT OF THE COMPLEX O-GLYCANS DERIVED FROM THE CERCARIAL GLYCOCALYX OF SCHISTOSOMA-MANSONI

Citation
Kh. Khoo et al., A UNIQUE MULTIFUCOSYLATED -3GALNAC-BETA-1-]4GLCNAC-BETA-1-]3GAL-ALPHA-1- MOTIF CONSTITUTES THE REPEATING UNIT OF THE COMPLEX O-GLYCANS DERIVED FROM THE CERCARIAL GLYCOCALYX OF SCHISTOSOMA-MANSONI, The Journal of biological chemistry, 270(29), 1995, pp. 17114-17123
Citations number
44
Categorie Soggetti
Biology
ISSN journal
00219258
Volume
270
Issue
29
Year of publication
1995
Pages
17114 - 17123
Database
ISI
SICI code
0021-9258(1995)270:29<17114:AUM->2.0.ZU;2-#
Abstract
The entire surface of the cercarial stage of the human blood fluke Sch istosoma mansoni is covered by a 1-mu m thick, highly immunogenic, fuc ose-rich glycocalyx (GCX). Using strategies based on enzymatic, chemic al, and mass spectrometric analysis, we have defined the structures of the major glycans released by reductive elimination from GCX. They co mprise a heterogeneous population of multifucosylated complex oligosac charides with the following nonreducing terminal sequences: +/- Fuc al pha 1 --> 2Fuc alpha 1 --> 3GalNAc beta 1 --> 4GlcNAc beta 1 --> 3Gal alpha 1 --> 3 (up arrow) +/- Fuc alpha 1 --> 2Fuc alpha 1 --> 2Fuc alp ha 1 STRUCTURE 1 Our structural data suggest that these tri- to pentaf ucosylated epitopes are carried on type 1, R-->Gal beta-1-->3GalNAc, a nd type 2, R-->Gal beta 1-->3(R-->GlcNAc beta-1-->6)GalNAc, core struc tures via repeat units of (3GalNAc beta 1-->4(Fuc alpha 1-->2Fuc alpha 1-->2Fuc alpha 1--3_GlcNAc beta-1-->3Gal alpha-->)(n)), where it is m ainly 0 and 1, and all sugars are in the pyranose form, The proposed s tructure represents the first instance where an alpha-galactosylated b eta-GalNAc(1-->4)-beta-GlcNAc sequence occurs as a repeating unit in a glycoprotein. It is also unique in being substituted with oligofucosy l appendages. The unusual oligosaccharide structures described here, p articularly the potentially immunodominant oligofucosyl moieties, are most likely responsible for the known potency of GCX in modulating var ious immune responses including complement activation, B cell mitogene sis, and delayed type hypersensitivity in schistosomiasis.