Figure 2.

¹H NMR spectra of type II GBS native polysaccharide (spectrum PS) and the saccharides of fractions 3 and 2 from Fig. 1 (spectra 3 and 2). The polysaccharide repeating unit consists of six hexoses as shown by six anomeric resonances at 4.90 (one proton), 4.84 (one proton), 4.66 (one proton), and 4.50 (two protons) ppm and a sialic acid as shown by its H-3 resonances. Spectrum 3 is nearly identical to spectrum PS, except for some differences resulting from the terminal residue, indicating that saccharide if has the same structure as the polymer. Spectrum 2 represents two repeating units, including 11 hexoses with 11 anomeric signals at 4.90 (2 signals), 4.84 (2 signals), 4.76 (1 proton), 4.66 (1 proton), 4.62 (1 proton), and 4.50 (4 proton) ppm, respectively, two sialic acids, and one aldonic acid. Note that the sialic acid residue was retained in all fragments as evidenced by its H-3 resonances.