Hybrid glycophorins from human erythrocyte membranes. I. Isolation and complete structural analysis of the hybrid sialoglycoprotein from Dantu-positive red cells of the N.E. variety.
The hybrid glycophorin in Dantu-positive human erythrocytes of the N.E. variety was not cleaved by treatment of intact cells with various proteases, in contrast to normal glycophorins. Therefore, it could be purified by phenol/saline extraction of membranes from trypsin-treated and chymotrypsin-treated red cells and subsequent gel filtration in the presence of Ammonyx-LO. The complete structure of the hybrid molecule, comprising 99 amino acid residues, was elucidated by sequence analyses of peptides prepared by chymotrypsin, trypsin, cyanogen bromide or V8 proteinase treatment. The N-terminal 39 residues and the glycosylation of the molecule were found to be indistinguishable from those of blood-group-s-specific glycophorin B. Conversely, the residues 39-99 were shown to be identical with the residues 71-131 of the major blood-group M-active or N-active sialoglycoprotein (glycophorin A). Hemagglutination inhibition assays revealed that the Dantu antigen represents a labile structure. The receptor might be located within the residues approximately 28-40 of the hybrid glycophorin, as judged from the effects of modifications of membranes. Our data provide an explanation for the previous findings that Dantu-positive cells (N.E. type) exhibit a protease-resistant N antigen and a qualitatively altered s antigen.
D000596:Amino Acids / Q000097:blood; D002241:Carbohydrates / Q000097:blood; D004910:Erythrocyte Membrane / Q000032:analysis*; D005838:Genotype; D006021:Glycophorins / Q000032:analysis* / Q000235:genetics / Q000276:immunology; D006801:Humans; D008951:MNSs Blood-Group System / Q000235:genetics / Q000276:immunology; D008565:Membrane Proteins / Q000097:blood* / Q000235:genetics / Q000276:immunology; D010455:Peptides / Q000097:blood; D012795:Sialoglycoproteins / Q000032:analysis*
D000596:Amino Acids; D002241:Carbohydrates; D006021:Glycophorins; D008951:MNSs Blood-Group System; D008565:Membrane Proteins; D010455:Peptides; D012795:Sialoglycoproteins