STRUCTURAL STUDIES OF THE O-ANTIGENIC POLYSACCHARIDES OF ESCHERICHIA-COLI O3 AND THE ENTEROAGGREGATIVE ESCHERICHIA-COLI STRAIN-17-2

The polysaccharide part of the lipopolysaccharide isolated from an ent eroaggregative Escherichia coli isolated from a young child with diarr hoea in Santiago, Chile (strain 17-2), has been investigated. Sugar an d methylation analyses of native and partially degraded polysaccharide together with H-1-NMR and C-13-NMR spectroscopies revealed that the p olysaccharide is composed of pentasaccharide repeating units. The stru cture of the repeating unit of E. coli strain 17-2 O-polysaccharide is : [GRAPHICS] The structure of the O-polysaccharide from E. coli O3 was shown to be identical to that of E. coli strain 17-2 by sugar and met hylation analyses and by H-1-NMR and C-13-NMR spectroscopies.