Structure of the O-polysaccharide from the lipopolysaccharide of Providencia alcalifaciens O33

•Lipopolysaccharide from Providencia alcalifaciens O33 was degraded with mild acid.•An O-polysaccharide, core and O-unit-bearing core oligosaccharides were obtained.•Structure of the O-polysaccharide repeat was established by 2D NMR spectroscopy.•Сomposition of the oligosaccharides was inferred by ESI mass spectrometry.

Mild acid degradation of the lipopolysaccharide from Providencia alcalifaciens O33 resulted in an O-polysaccharide along with core and O-unit-bearing core oligosaccharides. Composition of the oligosaccharides was inferred by ESI mass spectrometry. Based on sugar and methylation analyses, Smith degradation and 1H and 13C NMR spectroscopy data, the following structure of the tetrasaccharide O-unit of the O-polysaccharide was established:Figure optionsDownload full-size imageDownload as PowerPoint slideAnother O-polysaccharide structure has been reported earlier for Providencia stuartii О33 but later found to belong to a P. stuartii О52 strain.

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