Structural studies of the O-antigenic polysaccharides from the enteroaggregative Escherichia coli strain 522/C1 and the international type strain from Escherichia coli O 178.
The structure of the O-antigenic polysaccharide (PS) from the enteroaggregative Escherichia coli strain 522/C1 has been determined. Component analysis and (1)H and (13)C NMR spectroscopy techniques were used to elucidate the structure. Inter-residue correlations were determined by (1)H,(1)H-NOESY and (1)H,(13)C-heteronuclear multiple-bond correlation experiments. The PS is composed of pentasaccharide repeating units with the following structure: [ structure: see text]. Analysis of NMR data reveals that on average the PS consists of four repeating units and indicates that the biological repeating unit contains an N-acetylgalactosamine residue at its reducing end. Serotyping of the E. coli strain 522/C1 showed it to be E. coli O 178:H7. Determination of the structure of the O-antigen PS of the international type strain from E. coli O 178:H7 showed that the two polysaccharides have identical repeating units. In addition, this pentasaccharide repeating unit is identical to that of the capsular polysaccharide from E. coli O9:K 38, which also contains O-acetyl groups.
Ali
Tara
T
Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden.
Urbina
Felipe
F
Weintraub
Andrej
A
Widmalm
Göran
G
D002240:Carbohydrate Sequence; D002849:Chromatography, Gas; D004926:Escherichia coli / Q000737:chemistry* / Q000145:classification; D008401:Gas Chromatography-Mass Spectrometry; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D019081:O Antigens / Q000737:chemistry*
D019081:O Antigens