Structure of the O-specific polysaccharide of Proteus penneri strain 25 containing N-(l-alanyl) and multiple O-acetyl groups in a tetrasaccharide repeating unit

Based on sugar and methylation analyses, O-deacetylation, Smith degradation, and 1H and 13C NMR spectroscopy, including 2D COSY, 1H-detected 1H, 13C heteronuclear single-quantum coherence (HSQC), and 1H-detected 1H, 13C heteronuclear multiple-bond connectivity (HMBC) experiments, the following structure of the O-specific polysaccharide of Proteus penneri strain 25 was established: where d-GlcN(l-Ala) is 2-(l-alanylamido)-2-deoxy-d-glucose.