13C-N.M.R.-spectral study of the binding of Gd3+ to glycophorin.
Natural-abundance, 13C-n.m.r. spectroscopy was used to study the binding of Gd3+ to glycophorin, and also to the tetrasaccharides isolated from glycophorin after treatment of the glycoprotein with NaOH-NaBH4. Gd3+ binds to the tetrasaccharide (both in the isolated, reduced form and when still attached to the native glycoprotein), and, especially, to the alpha-NeuAc residues. In order to cause severe line-broadening of the 13C resonances of alpha-NeuAc, the ratios of the alpha-NeuAc residues of glycophorin, and of the isolated, reduced tetrasaccharide, to Gd3+ were much higher than that needed for causing similar broadening for 2-O-methyl-alpha-NeuAc-Gd3+ solutions. These results indicate that the other carbohydrate residues of the tetrasaccharide may be involved in the binding of Gd3+, producing a stronger metal-ion-binding effect.
D001665:Binding Sites; D005682:Gadolinium; D006021:Glycophorins; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D009844:Oligosaccharides; D011485:Protein Binding; D012795:Sialoglycoproteins
D006021:Glycophorins; D009844:Oligosaccharides; D012795:Sialoglycoproteins; D005682:Gadolinium