Synthetic TN glycopeptide related to human glycophorin AM. High-field proton and carbon-13 nuclear magnetic resonance study.
Three 2-acetamido-2-deoxy-alpha-D-galactopyranoses attached to Ser2, Thr3 and Thr4 of the amino-terminal portion of glycophorin AM are responsible for the so-called TN blood group specificity. The corresponding glycopeptide H2N-Ser-Ser*-Thr*-Gly-OH obtained by a stepwise peptide coupling strategy was submitted to a detailed high-field nuclear magnetic resonance (n.m.r.) analysis. 13C-n.m.r. spectrum confirms the validity of previous assignments made on M sialo and asialoglycopeptides obtained by specific degradation of human glycophorin AM. In addition, the 400 MHz 1H-n.m.r. spectrum allowed most of the proton resonances to be assigned. A careful examination of the chemical shifts and coupling constants revealed some interesting features of the conformational properties of the GalNAc-Ser and GalNAc-Thr linkage as well as of the rotational isomerism of Thr and Ser side-chains. The data give conclusive evidence that high-field n.m.r. spectroscopy can be successfully used to gain structural and dynamic information on rather sophisticated glycopeptides.
D001789:Blood Group Antigens; D002240:Carbohydrate Sequence; D006020:Glycopeptides / Q000138:chemical synthesis*; D006021:Glycophorins; D006801:Humans; D007202:Indicators and Reagents; D009682:Magnetic Resonance Spectroscopy; D012694:Serine; D012795:Sialoglycoproteins; D013912:Threonine
D001789:Blood Group Antigens; D006020:Glycopeptides; D006021:Glycophorins; D007202:Indicators and Reagents; D012795:Sialoglycoproteins; D013912:Threonine; D012694:Serine