The O-specific polysaccharides from Phyllobacterium trifolii PETP02(T) LPS contain 3-C-methyl-D-rhamnose

Abstract

The O-specific polysaccharides of Phyllobacterium trifolii PETP02(T), a microsymbiont of Trifolium pratense, were obtained by mild acid hydrolysis of the lipopolysaccharide and studied by chemical analyses, mass spectrometry, and (1)H and (13)C NMR spectroscopy, including homonuclear ((1)H,(1)H DQF-COSY, TOCSY, NOESY) and heteronuclear ((1)H,(13)C HSQC, HMQC, HMBC) experiments. It was revealed that α-D-rhamnose and β-3-C-methyl-D-rhamnose (evalose) were the only components of two identified O-polysaccharides. The major O-polysaccharide was found to consist of linear hexasaccharide repeating units, while the other minor one, is composed of disaccharide repeats. The following structures of two O-polysaccharides were established: → 2)-β-D-Rhap3CMe-(1 → 3)-α-D-Rhap-(1 → 3)-α-D-Rhap-(1 → 2)-β-D-Rhap3CMe-(1 → 3)-α-D-Rhap-(1 → 2)-α-D-Rhap-(1 → and → 2)-β-D-Rhap3CMe-(1 → 3)-α-D-Rhap-(1 →.

Keywords: 3-C-Methylrhamnose; Evalose; Lipopolysaccharide; O-Specific polysaccharide; Phyllobacterium trifolii; Rhamnose.