Structure of O-Antigen and Functional Characterization of O-Antigen Gene Cluster of Salmonella enterica O47 Containing Ribitol Phosphate and 2-Acetimidoylamino-2,6-dideoxy-L-galactose

摘要

An O-polysaccharide was isolated by mild acid degradation of the lipopolysaccharide of Salmonella enterica O47 and studied by sugar analysis along with one- and two-dimensional ~1H- and ~(13)C-NMR spectroscopy. The following structure of the linear ribitol phosphate-containing repeating unit of the O -polysaccharide was established: →2)-D-Ribitol-5-P-(O→6)-α-D-Gakp-(1→3)-α-L-FucpNAm-(1→3)-β-D-GlcpNAc-(1→,where FucNAm stands for 2-acetimidoylamino-2,6-dideoxy-L-galactose. About 10% of Gal is O-acetylated at position 4 and another minor O-acetyl group is present at an undetermined position. Functions of the S. enterica O47 antigen biosyn-thetic genes were tentatively assigned by comparison with gene databases and found to be in agreement with the O-polysaccharide structure. A comparison of the O-antigen gene clusters of S. enterica O47 and E. coli O145 suggested their close evolutionary relationship.