2TEDA School of Biological Sciences and Biotechnology and 3Tianjin Key Laboratory for Microbial Functional Genomics, TEDA College, Nankai University, 23 HongDa Street, TEDA, Tianjin 300457, P. R. China
* To whom correspondence should be addressed.
Received August 21, 2008; Revision received October 16, 2008
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 13C-NMR spectroscopy. The following structure of the linear ribitol phosphate-containing repeating unit of the O-polysaccharide was established:
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 biosynthetic 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.
KEY WORDS: Salmonella enterica, lipopolysaccharide, bacterial polysaccharide structure, acetimidoyl group, ribitol phosphate, O-antigen gene cluster