Structure of the O-specific polysaccharide of a serologically separate strain Proteus penneri 2 from a new proposed serogroup O66

O-specific polysaccharide chain of Proteus penneri strain 2 lipopolysacchar ide was studied by full and partial acid hydrolysis, Smith degradation, met hylation analysis, and NMR spectroscopy, including two-dimensional rotating -frame NOE spectroscopy (ROESY) and H-1, C-13 heteronuclear multiple-quantu m coherence (HMQC) experiments. Together with D-glucose and 2-acetamido-2-d eoxy-D-glucose, the polysaccharide was found to contain two rarely occurrin g sugars, 6-deoxy-L-talose (L-6dTal) and 2,3-diacetamido-2,3,6-trideoxy-L-m annose (L-RhaNAc3NAc), and the following structure of a non-stoichiometrica lly O-acetylated tetrasaccharide repeating unit was established: [GRAPHICS] O-specific polysaccharide studied has a unique composition and structure an d, accordingly, P. penneri 2 is serologically separate among Proteus strain s. Therefore, we propose for P, penneri 2 a new Proteus O-serogroup O66 whe re this strain is at present the single representative.