O-Specific chain structure from the lipopolysaccharide fraction of Pseudomonas reactans: a pathogen of the cultivated mushrooms

An O-specific polysaccharide containing 2-acetamidino-2-deoxy-β-d-glucopyranose (Glcp2Am), 2,4-diacetamido-2,4,6-trideoxy-β-d-glucopyranose (QuipNAc4NAc, bacillosamine) and 2,4-di-(N-acetyl-l-alanylamino)-2,4,6-trideoxy-β-d-glucopyranose (QuipNAlaAc4NAlaAc) was isolated from the phenol-soluble lipopolysaccharide fraction of the mushroom-associated bacterium Pseudomonas reactans. The structure, determined by means of chemical analysis and 1D and 2D NMR spectroscopy, showed a linear trisaccharide-repeating unit, as shown below:→3)-β-d-QuipNAlaAc4NAlaAc-(1→3)-α-d-Glcp2Am-(1→3)-α-d-QuipNAc4NAc(1→To our knowledge, this is the first complete O-chain structure reported for the lipopolysaccharide of a mushroom-associated bacterium.