Structural studies of the M blood group determinant

Abstract

Structural studies of homozygous glycophorin A M were undertaken by monitoring the 13C methyl resonances of 13C reductively methylated glycophorin A M (contains five N ϵ,N-[ 13 C] dimethyl Lys residues, and the N-terminal N α,N-[ 13C] dimethyl Ser residues) in various forms of glycosylation. The results indicate that removal of the α- d-NeuAc residues does not affect the structure about the N-terminal Ser residue. However, removal of the fifteen O-linked oligosaccharide units results in a structural effect about the N-terminal Ser residue. Partial methylation experiments performed on native glycophorin A M and deglycosylated glycophorin A M indicate that methylation of the lysine residue(s) may influence the structure about the N-terminal Ser residue, especially in the case of deglycosylated A M.