Structural Elucidation of the O-Antigenic Polysaccharide from Escherichia coli O44: H18

Authors


G. Widmalm, Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden
Fax:+46 8 154908.

Abstract

The O-antigen polysaccharide of the lipopolysaccharide from the enteroaggregative Escherichia coli O44:H18 has been investigated. Sugar and methylation analysis, 1H- and 13C-NMR spectroscopy revealed that the polysaccharide is composed of pentasaccharide repeating units. The sequence of sugar residues was determined by use of two-dimensional nuclear Overhauser effect spectroscopy and heteronuclear multiple bond correlation experiments. The structure of the repeating unit of the O-antigen from Escherichia coli O44:H18 is as follows.

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Abbreviations
COSY

correlated spectroscopy

HMBC

heteronuclear multiple bond correlation

NOESY

two-dimensional nuclear Overhauser effect spectroscopy

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