Membrane glycophorins in Sta blood group erythrocytes

J Biol Chem. 1986 Apr 25;261(12):5544-52.


Structural and immunochemical studies of glycophorins isolated from erythrocytes of an individual homozygous for the M Sta blood group phenotype are described. Reactivities with specific monoclonal antibodies indicated that two major M and N glycophorins were present. The M and N Sta glycophorins were resolved by Lens culinaris lectin affinity chromatography. The N species was not held on the lectin but the M species, like control alpha glycophorins, was retained and could be eluted with alpha-methylmannoside. The two proteins were present in almost equimolar amounts. Studies of the CNBr fragments provided evidence that the structure of M Sta glycophorin is the same as that of the usual M alpha glycophorin but that the N Sta glycophorin is a variant. The amino-terminal octapeptides of the M and N species were similar in amino acid and carbohydrate composition to those isolated, respectively, from M and N alpha glycophorins. The studies focused on CNBr glycopeptide B that, in control alpha glycophorins, extends from amino acid residues 9 to 81. The fragment from the M species exhibited properties identical to those of the corresponding fragment of control alpha glycophorins in terms of size, chromatographic behavior, amino acid and carbohydrate contents and compositions, the presence of O-glycosidically linked saccharides and a single Asn-linked carbohydrate unit. The structures of the O-linked units were inferred experimentally to be NeuAc(alpha 2,3)Gal-(beta 1,3)GalNAc and NeuAc(alpha 2,3)Gal(beta 1,3) [NeuAc(alpha 2,6)]GalNAc, present in a ratio similar to that found in controls; and the Asn-linked unit also appeared to be as in the control. The tryptic glycopeptide pattern of the M Sta glycophorin CNBr fragment B was identical to the pattern of the corresponding control fragment, and the composition of the tryptic peptides suggested sequence identity with the control fragment. In contrast, the N Sta glycophorin yielded two CNBr glycopeptides B; both contained fewer amino acid residues and virtually lacked Man and GlcNAc, indicating the absence of the Asn-linked carbohydrate. The much decreased levels of these carbohydrates in the intact N protein, corroborated the latter finding. The O-glycosidic saccharides appeared similar to those found in control alpha glycophorins. However, the tryptic glycopeptide pattern of the variant differed from control M or N alpha glycophorins, suggesting a deletion of a large segment of the molecule near residues 40-61 and/or a substitution of methionine for a residue upstream from residue 40.(ABSTRACT TRUNCATED AT 400 WORDS)

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acids / analysis
  • Antibodies, Monoclonal
  • Carbohydrates / analysis
  • Chromatography, Affinity
  • Chromatography, Gel
  • Cyanogen Bromide / pharmacology
  • Electrophoresis, Polyacrylamide Gel
  • Erythrocyte Membrane / analysis*
  • Glycophorins / analysis*
  • Homozygote
  • Humans
  • Immunosorbent Techniques
  • MNSs Blood-Group System*
  • Oligosaccharides / analysis
  • Peptide Fragments / analysis
  • Phenotype
  • Sialoglycoproteins / analysis*


  • Amino Acids
  • Antibodies, Monoclonal
  • Carbohydrates
  • Glycophorins
  • MNSs Blood-Group System
  • Oligosaccharides
  • Peptide Fragments
  • Sialoglycoproteins
  • Cyanogen Bromide