Structure of a complex-type sugar chain of human glycophorin A

Abstract

Tryptic glycopeptide T1 of human glycophorin A [Tomita, M., & Marchesi, V. T. (1975) Proc. Natl. Acad. Sci. U.S.A. 72, 2964-2968] was subjected to hydrazinolysis. After N-acetylation, the complex-type oligosaccharides were isolated by gel filtration. The major neutral oligosaccharide (2000 molecular weight) was purified by a combination of ion-exchange and gel-permeation chromatography. Treatments with endo- and exo-glycosidases, periodate oxidation, and methylation analysis indicated that the major neutral oligosaccharide has the following structure: Gal beta 1 leads to -4GlcNAc beta 1 leads to 2Man alpha 1 leads to 6(GlcNAc beta 1 leads to 4)(Gal beta 1 leads to -4GlcNAc beta 1 leads to 2Man alpha 1 leads to 3)Man beta 1 leads to 4GlcNAc beta 1 leads to 4-(Fuc alpha 1 leads to 6)GlcNAc. This oligosaccharide was retained by Ricinus communis agglutinin-Sepharose and retarded by Sepharose 4B coupled with erythroagglutinating E4 isolectin from Phaseolus vulgaris. Retention by concanavalin A-Sepharose was observed only after treatment of the oligosaccharide with beta-galactosidase.