OLIGOSACCHARIDES RELATED TO TUMOR-ASSOCIATE ANTIGENS .2. CONFORMATIONAL-ANALYSIS OF THE TRISACCHARIDE A-L-FUCP-(1-]2)-BETA-D-GALP-(1-]3)-BETA-D-GALPNAC, EPITOPE STRUCTURE RECOGNIZED BY THE MBR1 ANTIBODY

The conformational space of the trisaccharide alpha-L-Fuc-(1 --> 2)-be ta-D-Gal-(1 --> 3)-beta-D-GalNAc-1-OPr (2) and of its component disacc haride moieties alpha-L-Fuc-(1 --> 2)-beta-D-Gal-1-OMe (3) and beta-D- Gal-(1 --> 3)-beta-D-GalNAc-1-OPr (4) was investigated with the aid of molecular-mechanics energy minimizations and molecular-dynamics simul ations. These calculations suggested the occurrence of two conformatio ns for each compound characterized by different phi and psi glycosidic angles. However, H-1-NMR investigation of D2O solutions of 2-4 indica ted a sure preference for one of the two conformers with a contributio n of the other one ranging from negligible to low.