J Carbohydr Chem 1997; 16: 927-46
The 0-polysaccharide of Shigella dysenteriae type 1 is made up of multiple repeats of the linear tetrasaccharide 3)-a-L-Rhap-(1-2)-a-D-Galp-(1-3)-a-D-GlcpNAc-(1 -3)-a-LRhap-(l-, for which the antigenic determinant for a murine monoclonal IgM antibody is the disaccharide a-L-Rhap-(1-2)-a-D-Galp. This disaccharide and various analogs have been studied by 2D NOESY, ROESY, and TOCSY NMR spectroscopy, in conjunction with proton spin-lattice relaxation rate measurements, restrained molecular mechanics, and restrained molecular dynamics with simulated annealing. It has been found that replacement of any single hydroxyl group in the determinant by a hydrogen atom, or replacement of any single hydroxyl group in the Gal residue by a fluorine atom has little if any influence on the conformation of the resulting derivatives.