STRUCTURAL MOTIFS OF THE DIMERIC LEWIS GLYCOLIPIDS AS DETERMINED BY NMR-SPECTROSCOPY AND MOLECULAR-DYNAMICS SIMULATIONS

Several monomeric and dimeric Lewis glycolipids have been investigated by NMR spectroscopy, and structural aspects were modelled by computer . From the pseudo-C-2-symmetric tetrasaccharide unit that forms the re cognition domain of the Lewis Y and Lewis b antigens, a totally C-2-sy mmetric tetrasaccharide was designed that contains the structural elem ent common to all Lewis antigens. Finally, a model for the presentatio n of dimeric Lewis antigens at membrane surfaces was derived. The over all shapes of the dimeric Lewis oligosaccharides are defined by the co nnectivity of the sugar residues within rigid tri- and tetrasaccharide building blocks.