Structure of an Acidic O-Specific Polysaccharide of the Bacterium Providencia alcalifaciens O7

O. V. Bystrova¹, G. V. Zatonskii¹, S. A. Borisova¹, N. A. Kocharova¹, A. S. Shashkov¹, Y. A. Knirel^1*, E. V. Kholodkova², and E. S. Stanislavskii²

¹Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninskii pr. 47, Moscow, 117913 Russia; fax: (7-095) 135-5328; E-mail: knirel@ioc.ac.ru

²Mechnikov Central Research Institute of Vaccines and Sera, Russian Ministry of Public Health, Pereulok Mechnikova 5a, Moscow, 103064 Russia; fax: (7-095) 916-2587

^* To whom correspondence should be addressed.

Received August 13, 1999

---

An acidic O-specific polysaccharide was obtained by mild acid degradation of the lipopolysaccharide of the bacterium Providencia alcalifaciens O7 and purified by gel chromatography followed by anion-exchange chromatography. On the basis of full acid hydrolysis, methylation, carboxyl reduction, selective cleavage with anhydrous hydrogen fluoride, and ¹H- and ¹³C-NMR spectroscopy, including two-dimensional ¹H,¹H homonuclear and H-detected ¹H,¹³C heteronuclear correlation spectroscopy and nuclear Overhauser effect spectroscopy (NOESY), the following structure of the linear tetrasaccharide repeating unit of the polysaccharide was established: [figure], where Rhap2Ac is 2-O-acetylrhamnopyranose.

---

KEY WORDS: O-antigen, lipopolysaccharide, bacterial polysaccharide, Providencia alcalifaciens

---