| Abstract: | The structure of the O‐antigen polysaccharide from Escherichia coli strain F171 has been determined. NMR analysis of the polysaccharide showed that it was composed of pentasaccharide repeating units. The 1H and 13C signals were assigned by 2D NMR techniques which revealed severe spectral overlap for key resonances at substitution positions. The structure of the repeating unit was deduced from 1H,13C HMBC and, in particular, by 1H,1H NOESY experiments as follows:  The structure is identical with that of the O‐antigen from Escherichia coli O25 previously determined by chemical degradation methods and the strain F171 should therefore belong to this serogroup. Copyright © 2003 John Wiley & Sons, Ltd. |
