The O-specific polysaccharides from Phyllobacterium trifolii PETP02T LPS contain 3-C-methyl-d-rhamnose

• Structures of the two O-polysaccharides of Phyllobacterium trifolii PETP02T were established.
• The major O-polysaccharide is built up of linear hexasaccharide repeating units.
• The minor O-polysaccharide is composed of disaccharide repeats.
• d-Evalose (3-C-methyl-d-rhamnose) was found in the both O-polysaccharides.

The O-specific polysaccharides of Phyllobacterium trifolii PETP02T, a microsymbiont of Trifolium pratense, were obtained by mild acid hydrolysis of the lipopolysaccharide and studied by chemical analyses, mass spectrometry, and 1H and 13C NMR spectroscopy, including homonuclear (1H,1H DQF-COSY, TOCSY, NOESY) and heteronuclear (1H,13C 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→

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