M. Staaf et al., Structure elucidation of the O-antigenic polysaccharide from the enteroaggregative Escherichia coli strain 62D(1), EUR J BIOCH, 262(1), 1999, pp. 56-62
The O-antigen polysaccharide of the lipopolysaccharide from the enteroaggre
gative Escherichia coli strain 62D(1) has been determined. Sugar and methyl
ation analysis together with H-1 and C-13 NMR spectroscopy revealed the com
ponents of the repeating unit. Two-dimensional NOESY and heteronuclear mult
iple-bend correlation experiments were used to deduce the sequence. H-1 and
C-13 NMR spectra indicate heterogeneity in the polysaccharide. Methylation
analysis and H-1 NMR spectra of native and Smith-degraded material show th
at the majority (65%) of the repeating units has the following structure:
-->2)-beta-D-Quip3NAc-(1-->3)-alpha-L-Rhap-(1-->3)-beta-D -Galp-(1-->3)-alp
ha-D-FucpNAc-(1-->alpha-D-Galp
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Minor resonances in the NMR spectra are consistent with the presence of rep
eating units which lack the alpha-D-Galp terminal residue (35%).