Structure of a polysaccharide from the lipopolysaccharide of Vibrio vulnificus clinical isolate YJ016 containing 2-acetimidoylamino-2-deoxy-l-galacturonic acid

A polysaccharide isolated after mild acid degradation of the lipopolysaccharide of Vibrio vulnificus clinical isolate YJ016 was found to contain l-Fuc, d-GlcpNAc, 2,4-diacetamido-2,4,6-trideoxy-d-glucose (di-N-acetylbacillosamine, d-QuiNAc4NAc), and 2-acetimidoylamino-2-deoxy-l-galacturonic acid (l-GalNAmA). The last sugar derivative was confirmed by correlations for nitrogen-linked protons in 2D TOCSY and ROESY spectra measured in a H2O–D2O mixture. The following structure of the polysaccharide was established by 1H and 13C NMR spectroscopy, including 2D ROESY and 1H,13C HMBC experiments:Figure optionsDownload as PowerPoint slidewhere the degree of 6-O-acetylation of the lateral β-GlcNAc residue is ∼70%.

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