Structure of a new neutral O-specific polysaccharide of Proteus penneri 34

The O-specific polysaccharide of Proteus penneri strain 34 was studied using 1H and 13C NMR spectroscopy, including 2D COSY, TOCSY, NOESY, and H-detected 1H,13C HMQC experiments. The following structure was established, which is unique among the known structures of Proteus O-antigens: →4)-β-d-Glcp-(1⃗3)-β-d-GalpNAc-(1⃗4)-β-d-GalpNAc-(1⃗4)-β-d-Galp-(1⃗. Accordingly, no cross-reaction was observed between P. penneri 34 O-antiserum and O-antigens of other Proteus strains. Therefore, the strain studied should belong to a new Proteus serogroup O65.