Structural Study of the Lipopolysaccharide O-Antigen Produced by the Emerging Cystic Fibrosis Pathogen Pandoraea pulmonicola

This is the first report on the molecular structure of the O-chain of the lipopolysaccharide produced by the emerging and highly virulent clinical isolate Pandoraea pulmonicola strain LMG 18108, an opportunistic human pathogen in cystic fibrosis patients. Monosaccharide analysis and 2D NMR spectroscopy revealed a novel polysaccharide, the structure of which consists of the trisaccharide repeating unit [->2-?-d-Quip3NAcyl-(1->4)-?-d-GalpNAc-(1->3)-?-d-GlcpNAc-1->]n. The quinovosamine residue was found to be linked by a very unusual acyl substituent, a five-membered-ring acyl residue, the 3-hydroxy-2,3-dimethyl-5-oxoprolyl group.