SOMATIC ANTIGENS OF PSEUDOMONAS-AERUGINOSA - THE STRUCTURE OF O-SPECIFIC POLYSACCHARIDE CHAINS OF P-AERUGINOSA O-3A, B-LIPOPOLYSACCHARIDE AND O-3A, D-LIPOPOLYSACCHARIDE

  • 1 January 1982
    • journal article
    • research article
    • Vol. 128  (1) , 81-90
Abstract
On mild acid degradation of P. aeruginosa O:3a,b and O:3a,d lipopolysaccharides O-specific polysaccharides were isolated. Both polysaccharides contained 2-acetamido-2,6-dideoxy-D-galactose, identified as fucosamine hydrochloride formed after hydrolysis with a very low yield. The other 2 components of the trisaccharide repeating unit, 2,3-diacetamido-2,3-dideoxy-D-mannuronic acid and 2,3-(1-acetyl-2-methyl-2-imidazolino-5,4)-2,3-dideoxy-D-mannuronic acid, were identified without isolation in their free state directly in the course of structural investigation of the polysaccharides. Both these monosaccharides have never before been found in nature. Solvolysis of either O:3a,b or O:3a,d polysaccharides with liquid HF resulted in the formation of the same trisaccharide, N-acetylfucosamine residue being the reducing end. The structure of this trisaccharide, which is the repeating unit of both polysaccharides, was deduced from the results of successive chemical modifications and 13C-NMR spectra recorded for every oligosaccharide formed. As a result, the acidic diaminosugars were converted into 2,3-diacetamido-2,3-dideoxy-D-mannose indistinguishable from authentic sample. The O-specific polysaccharides O:3a,b and O:3a,d differed in the configuration of the glycosidic bond of N-acetylfucosamine residue only and had the following structures: .fwdarw. 4)D-ManImU(.beta.1 .fwdarw. 4)DMan(NAc)2U(.beta.1 .fwdarw. 3)DFucNAc(.beta.1- and .fwdarw. 4)DManImU(.beta.1 .fwdarw. 4)DMan(NAc)2U(.beta.1 .fwdarw. 3)DFucNAc(.alpha.1- where DManImU is 2,3-(1-acetyl-2-methyl-2-imidazolino-5,4)-2,3-dideoxy-D-mannuronic acid, DMan(NAc)2U is 2,3-diacetamido-2,3-dideoxy-D-mannuronic acid and DFucNAc is 2-acetamido-2,6-dideoxy-D-galactose. The structures established were in agreement with optical rotations and assignments of all the signals in the 13C-NMR spectra of the polysaccharides.