Full structure of the O-specific polysaccharide of Proteus mirabilis O24 containing 3,4-O-[(S)-l-carboxyethylidene]-D-galactose

The structure of a neutral polysaccharide isolated by degradation with dilu te acetic acid of the lipopolysaccharide (LPS) of P. mirabilis O24 has been determined recently [E. Literacka et al., FEBS Lett., 456 (1999) 227-231]. Further studies of this LPS using alkaline degradation and hydrolysis at p H 4.5 showed that the polysaccharide chain includes an acetal-linked pyruvi c acid residue, which is removed completely during delipidation with acetic acid. A revision using H-1 and C-13 NMR spectroscopy and methylation analy sis resulted in determination of the following full structure of the repeat ing unit of the O-specific polysaccharide: [GRAPHICS] where D-Gal3,4(S-Pyr) is 3,4-O-[(S)-1-carboxyethylidene]-D-galactose. (C) 2 000 Elsevier Science Ltd. All rights reserved.