title: Membrane glycophorins of Dantu blood group erythrocytes.
abstract: Glycophorins of erythrocytes of two unrelated individuals who exhibit the Dantu blood group phenotype were studied. Immunoblots indicated that erythrocytes of each individual contained a complement of a normal alpha-glycophorin (glycophorin A) and a variant N-glycophorin. delta-Glycophorin (glycophorin B) was present in one donor's cells but not the other's; the s and N phenotypes of the latter's erythrocytes may derive from the variant glycophorin. The variant glycophorin is of a smaller size, does not bind to Lens culinaris lectin agarose, and lacks residues approximately 40-60 of alpha-glycophorin and its single asparagine-linked carbohydrate; it contains approximately 2 less O-glycosidically bound units whose structures are identical to those found in alpha-glycophorins. All these properties are characteristic of delta-glycophorin. The variant is related to alpha-glycophorin in the carboxyl-terminal region as shown by reaction with a specific antiserum. Sequence analyses of a mixture of chymotryptic peptides of a CNBr fragment of the variant glycophorin identified the sequence Val-His-Arg-Phe-Thr-Val-Pro-Glu-Ile-Thr-Leu-Ile-Ile that contains the junction point of delta- and alpha-glycophorins spanning residues 33-38/39 of delta-glycophorin and residues 71/72-77 of alpha-glycophorin. Sequence analysis of a mixture of CNBr fragments allowed us to conclude that the variant originates from delta-s- rather than delta-S-glycophorin. The quantity of the variant Dantu glycophorin when compared to alpha-glycophorin differed in the two individuals, the ratio being 2/1 in one individual's cells and 0.5/1 in the other's. This may reflect that the two donors belong to different varieties of Dantu phenotypes. Together, the evidence indicates that both donors' erythrocytes contain a (delta-alpha) variant glycophorin, whose amino terminus originates from delta-s-glycophorin and the carboxyl end from alpha-glycophorin with a junction point around residues 39 of delta- and 71 of alpha-glycophorins. The results suggest that the unique junction region may be characteristic of the Dantu phenotype.
authors.forename: O O
authors.initials: OO
authors.lastname: Blumenfeld
authors.forename: A J
authors.initials: AJ
authors.lastname: Smith
authors.forename: J J
authors.initials: JJ
authors.lastname: Moulds
mesh_terms: D000595:Amino Acid Sequence; D001789:Blood Group Antigens; D002846:Chromatography, Affinity; D002850:Chromatography, Gel; D004910:Erythrocyte Membrane / Q000032:analysis*; D006021:Glycophorins / Q000097:blood*; D006595:Hexosamines / Q000032:analysis; D006801:Humans; D007163:Immunosorbent Techniques; D012794:Sialic Acids / Q000032:analysis; D012795:Sialoglycoproteins / Q000097:blood*
chemical_list: D001789:Blood Group Antigens; D006021:Glycophorins; D006595:Hexosamines; D012794:Sialic Acids; D012795:Sialoglycoproteins