A 2D-1H-n.m.r. study of some Shigella flexneri O-polysaccharides.

A 1H-n.m.r. study of the O-polysaccharides from different types of Shigella flexneri has been performed. With the aid of 2D-n.m.r. techniques, namely, J-resolved, spin-spin correlation, and NOESY experiments, most of the structural features of these polysaccharides could be deduced. Sequences could generally be obtained from the NOESY experiments. When using a prolonged mixing time in these experiments, cross-peaks due to spin diffusion from one anomeric proton to the anomeric proton of an adjacent residue could be obtained, thereby giving complementary sequence information.