The Full Structure of the Carbohydrate Chain of the Lipopolysaccharide of Providencia alcalifaciens O19

An oligosaccharide isolated from the lipopolysaccharide of Providencia alcalifaciens O19 was found to consist of a single O‐antigen repeating unit linked to the core. The full oligosaccharide structure was elucidated by 2D ¹H, ¹³C, and ³¹P NMR spectroscopy. It was shown that the inner core region has the same structure as in other Providencia strains studied, whereas the outer core is structurally diverse between Providencia strains. A pyruvic acid acetal was found in the isolated oligosaccharide and in the long‐chain O‐antigen, whose structure has been established earlier. The biological O‐unit structure was elucidated in the short‐chain lipopolysaccharide.

Keywords:

• Providencia alcalifaciens
• O‐polysaccharide
• O‐unit
• Core oligosaccharide
• Lipopolysaccharide structure

Acknowledgments

This work was supported by the Russian Foundation for Basic Research (project 08‐04‐92221) and the Council on Grants at the President of the Russian Federation for Support of Young Russian Scientists (project MK‐641.2008.4). A.N.K. thanks the Borstel Foundation for scholarship.