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Detection of Multisulphated N‐Linked Glycans in the L2/HNK‐1 Carbohydrate Epitope Expressing Neural Adhesion Molecule P 0
Author(s) -
Field M. C.,
Wing D. R.,
Dwek R. A.,
Rademacher T. W.,
Schmitz B.,
Bollensen E.,
Schachner M.
Publication year - 1992
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1992.tb09353.x
Subject(s) - epitope , glycan , sialic acid , neural cell adhesion molecule , biochemistry , glycoprotein , chemistry , glycolipid , glycosylation , polysialic acid , residue (chemistry) , carbohydrate , biology , cell adhesion , antigen , cell , immunology
P 0 , the most abundant glycoprotein of PNS myelin, is a homophilic and heterophilic adhesion molecule. P 0 is known to contain a glycofonn population that expresses the L2/HNK‐1 carbohydrate epitope found on other neural adhesion molecules, and to be functionally implicated centrally in neural cell adhesion and neurite outgrowth. This carbohydrate epitope has been characterized previously from glycolipid structures and contains a sulphated glucuronic acid residue. However, the L2/HNK‐1 carbohydrate epitope has not been characterized in glycoproteins. Because P 0 possesses only one glycosylation sequon, the number of P 0 glycoforms is equal to the heterogeneity of the glycan species. Here we report that the carbohydrate analysis of L2/HNK‐1‐reactive P 0 showed the presence of anionic structures containing sialic acid and sulphate in various combinations. At least one sulphate residue was present in 80% of the monosaccharide sequences, and 20% contained three sulphates. High‐resolution P4 gel chromatography of the desialylated and desulphated oligosaccharides showed substantial heterogeneity of monosaccharide sequences. Sequential exoglycosidase digestions indicated that the majority of the structures were of the hybrid class, although the sulphated structures were found to be en‐doglycosidase H‐resistant.