Structural characterization of the carbohydrate backbone of the lipopolysaccharide of Vibrio parahaemolyticus O-untypeable strain KX-V212 isolated from a patient

Abstract Vibrio parahaemolyticus strain KX-V212 of a novel serotype, which does not belong to any of the known 13 O-serotypes of this vibrio, was isolated from a patient. Its O-antigen harbors a unique strain-specific O-antigenic factor(s), in addition to that shared by the O-antigen of V. parahaemolyticus serotype O2. A carbohydrate backbone nonasaccharide was isolated from the lipopolysaccharide (LPS) of strain KX-V212 by dephosphorylation, reduction and deacylation and found to consist of one residue each of d -glucose, d -galactose, d -GlcN, 3-deoxy- d - manno -oct-2-ulosonic acid (Kdo) and 5-acetamido-7-( N -acetyl- d -alanyl)amino-3,5,7,9-tetradeoxy- d - glycero - d - galacto -non-2-ulosonic acid (Non5Ac7Ala), and two residues each of d -GlcA and l - glycero - d - manno -heptose ( ld -Hep). Analysis of the isolated and deacylated lipid A showed that this oligosaccharide was an artifact resulting from a loss of one GlcN residue from the lipid A backbone. Therefore, the carbohydrate backbone of the LPS is a decasaccharide having the structure shown below. The initial LPS contains also d -GalA and phosphoethanolamine at unknown positions. Both similarity and differences are observed between the LPS of V. parahaemolyticus serotype O2 and strain KX-V212. Download full-size image