Structure of the O-polysaccharide from the lipopolysaccharide of Providencia alcalifaciens O60

An O-polysaccharide (O-antigen) was isolated by mild acid degradation of the lipopolysaccharide of Providencia alcalifaciens O60 and studied by sugar and methylation analyses as well as 1H and 13C NMR spectroscopy, including 2D ROESY and 1H,13C HMBC experiments in D2O and a ROESY experiment in a 9:1 H2O–D2O mixture to reveal correlations for NH protons. It was found that the polysaccharide is built up of linear pentasaccharide repeating units containing an amide of d-glucuronic acid with l-serine and has the following structure:Figure optionsDownload full-size imageDownload as PowerPoint slideThe O-antigen studied is structurally and serologically closely related to the O-antigen of Proteus vulgaris O44.

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