STRUCTURE OF THE ACID-LABILE GALACTOSYL PHOSPHATE-CONTAINING O-ANTIGEN OF THE BACTERIUM PROTEUS-VULGARIS-OX19 (SEROGROUP-O1) USED IN THE WEIL-FELIX-TEST

The structure of the O-specific polysaccharide chain of Proteus vulgar is OX19 lipopolysaccharide which determines the O1 specificity of Prot eus and is used in the Weil-Felix test for diagnostics of rickettsiosi s was established. On the basis of H-1- and C-13-NMR spectroscopy, inc luding two-dimensional correlation spectroscopy (COSY), H-detected H-1 , C-13 heteronuclear multiple-quantum coherence (HMQC), and rotating-f rame nuclear Overhauser effect spectroscopy (ROESY), it was found that the polysaccharide consists of branched pentasaccharide repeating uni ts containing D-galactose, 2-acetamido-2-deoxy-D-glucose, 2-acetamido- 2-deoxy-D-galactose, and 2-acetamido-2,6-dideoxy-D-glucose (QuiNAc, tw o residues), which are connected to each other via a phosphate group ( P): [GRAPHICS] The polysaccharide is acid-labile, the glycosyl phospha te linkage being cleaved at pH 4.5 (70 degrees C) to give a phosphoryl ated pentasaccharide with a galactose residue at the reducing end. Str uctural analysis of the oligosaccharide and a product of its dephospho rylation with 48% hydrofluoric acid using H-1- and C-13-NMR spectrosco py and electrospray ionization mass spectrometry confirmed the structu re of the polysaccharide.