title: Structural analysis of glycophorin A from Miltenberger class VIII erythrocytes.
abstract: The major human erythrocyte membrane sialoglycoprotein (glycophorin A or MN glycoprotein) was purified from the erythrocytes of two individuals heterozygous for the Mi-VIII gene in the Miltenberger subsystem of the MNSs blood-group system. The complete structure of a tryptic glycopetide from glycophorin A comprising the residues 40-61 was deduced from automated and manual sequence analyses. The Mi-VIII-specific glycophorin A was found to exhibit an arginine----threonine exchange at position 49. The threonine residue was found to be glycosylated. Hemagglutination and hemagglutination inhibition assays demonstrated that one of the Mi-VIII-characteristic antigenic determinants (Anek) is located within the residues 40-61 of glycophorin A. Furthermore, erythrocytes from the two Mi-VIII heterozygotes reacted only weakly with anti-EnaKTsera, suggesting that the Mi-VIII-specific glycophorin A does not express the EnaKT antigen that is located within the positions 46-56 of normal glycophorin A. Our data suggest that the Mi-VIII-specific glycophorin A represents the evolutionary link between normal glycophorin A and the Mi-VIII-specific molecule which exhibits arginine----threonine and tyrosine----serine exchanges at the positions 49 and 52, respectively. Our data also provide an explanation for the close serological similarity between Mi-VII and Mi-VIII erythrocytes.
authors.affiliation: Centre Regional Transfusion Sanguine de Nantes.
authors.forename: W
authors.initials: W
authors.lastname: Dahr
authors.forename: V
authors.initials: V
authors.lastname: Vengelen-Tyler
authors.forename: E
authors.initials: E
authors.lastname: Dybkjaer
authors.forename: K
authors.initials: K
authors.lastname: Beyreuther
mesh_terms: D000595:Amino Acid Sequence; D000606:Amino Sugars / Q000032:analysis; D004910:Erythrocyte Membrane / Q000032:analysis; D004912:Erythrocytes / Q000032:analysis* / Q000276:immunology; D006021:Glycophorins / Q000032:analysis* / Q000276:immunology; D006801:Humans; D008969:Molecular Sequence Data; D010455:Peptides / Q000032:analysis; D012795:Sialoglycoproteins / Q000032:analysis*
chemical_list: D000606:Amino Sugars; D006021:Glycophorins; D010455:Peptides; D012795:Sialoglycoproteins