Structure of the O-Specific Polysaccharide of the Bacterium Providencia alcalifaciens O23 Containing a Novel Component: an Amide of D-Glucuronic Acid with N^epsilon-(1-Carboxyethyl)lysine

N. A. Kocharova,¹ O. V. Shcherbakova,¹ A. S. Shashkov,¹ Yu. A. Knirel,^1,2 N. K. Kochetkov,¹ E. V. Kholodkova,³ and E. S. Stanislavsky³

¹Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, Leninskii pr. 47, Moscow, 117913 Russia; fax: (7-095) 135-53-28; E-mail: knirel@ioc.ac.ru

²To whom correspondence should be addressed.

³Mechnikov Central Research Institute for Vaccines and Sera, Ministry of Public Health of Russian Federation, Pereulok Mechnikova 5a, Moscow, 103064 Russia; fax: (7-095) 916-25-87.

Submitted October 25, 1996; revision submitted January 20, 1997.

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An acidic O-specific polysaccharide was obtained by mild acid degradation of the lipopolysaccharide of the bacterium Providencia alcalifaciens O23 and found to contain D-glucose, D-galactose, 2-acetamido-2-deoxy-D-galactose, and N^epsilon-(1-carboxyethyl)-N^alpha-(D-glucuronoyl)lysine. On the basis of full and partial acid hydrolyses, selective solvolysis with anhydrous hydrogen fluoride, and ¹H- and ¹³C-NMR spectroscopy, including two-dimensional correlation spectroscopy (COSY), H-detected heteronuclear ¹H,¹³C multi-quantum coherence (HMQC), and rotating-frame nuclear Overhauser effect spectroscopy (ROESY), the following structure of the liner tetrasaccharide repeating unit of the polysaccharide was established (see full article for figure).

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KEY WORDS: O-antigen, bacterial polysaccharide, D-glucuronic acid, amide, N^epsilon-(1-carboxyethyl)lysine, structure, Providencia alcalifaciens.

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