Structural analysis of the O-polysaccharide from the lipopolysaccharide of Azospirillum brasilense S17

A mixture of two structurally distinct neutral O-polysaccharides was obtained by mild acid degradation of the lipopolysaccharide isolated by the phenol/water extraction from the asymbiotic diazotrophic rhizobacterium Azospirillum brasilense S17. The following structures of the O-polysaccharides were established by composition and methylation analyses, Smith degradation, and 1H and 13C NMR spectroscopy, including a 2D NOESY experiment:Figure optionsDownload full-size imageDownload as PowerPoint slide where l-Rha2Me stands for 2-O-methyl-l-rhamnose and SHb for the (S)-3-hydroxybutanoyl group. The occurrence of two distinct polysaccharides is reported for the first time in Azospirillum spp.

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