Occurrence ofO-Glycosidically Peptide-Linked Oligosaccharides of Poly-N-Acetyllactosamine Type (Erythroglycan II) in the I-Antigenically Active Sendai Virus Receptor Sialoglycoprotein GP-2

摘要

Unique high molecular weight (M.W. 4,000–9,000) sugar chains termed erythroglycan II have been obtained from alkali/sodium borohydride digests of I-active asialoglycoprotein derived from sialoglycoprotein GP-2, which was isolated recently from bovine erythrocyte membranes as Sendai virus receptor (Suzuki, Y.et al. (1983)J. Biochem. 93, 1621–1633; (1984)ibid, 95, 1193–1200). It was found that these sugar chains comprise about 40of total alkali-labile oligosaccharides of asialo GP-2 and contain endo-β-galactosidase (Flavobacterium keratolyticus)-resistant highly branched and heterogeneous oligosaccharides of poly-N-acetyllactosamine type which are linkedO-glycosidically to the peptide backbone through N-acetyl galactosamine. Erythroglycan II also contains endo-β-galactosidase-susceptible straight terminal polylactosaminyl side chains. A major oligosaccharide released by the enzyme cochromatographed with Galβ1-4GlcNAcβ-3Gal.Inhibitory activity of Sendai virus-mediated hemagglutination and the receptor activity for the virus were reduced significantly but not completely by the endo-β-galactosidase. These results indicate that both linear and branched sialosylpolylactosamine sequences in erythroglycan II are important for the reception of the virus into the ta