SYNTHESIS AND CONFORMATIONAL AND NMR-STUDIES OF ALPHA-D-MANNOPYRANOSYL AND ALPHA-D-MANNOPYRANOSYL-(1-]2)-ALPHA-D-MANNOPYRANOSYL LINKED TO L-SERINE AND L-THREONINE

Alpha-D-Mannopyranosyl and a-D-mannopyranosyl-(1 --> 2)-alpha-D-mannopyranosyl linked to L-serine and L-threonine have been synthesised as model substances for the linkage region in certain O-linked glycoproteins. Metropolis Monte Carlo simulations were performed with a modified version of the GESA program. to yield theoretical NOEs and interatomic distances as ensemble-average values, and these were compared with results from steady-state NOE experiments. The NOEs were determined as ensemble-average and as global minimum values. NMR chemical shift differences, obtained for signals of the glycopeptides relative to those of the respective monomers, were interpreted in terms of short inter-residue atomic distances as found within the global minima, and on the basis of averaged distances derived from Monte Carlo simulations.