STRUCTURE OF ANOTHER ABEQUOSE-CONTAINING O-POLYSACCHARIDE FROM CITROBACTER FREUNDII O22 STRAIN PCM 1555

E. Katzenellenbogena, N.A. Kocharovab, Ph.V. Toukachb, S. Górskaa, A. Korzeniowska-Kowala, M. Bogulskaa, A. Gamiana, Y.A. Knirelb

aL. Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Weigla, Wroclaw, Poland
bN. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia

KEYWORDS: Lipopolysaccharide, Citrobacter, O-Specific polysaccharide structure, Endotoxin, Serological classification

FEMS immunology and medical microbiology, 2009, v. 344(13), pp. 1724-1728

DOI: 10.1016/j.carres.2009.06.005


The lipopolysaccharide of Citrobacter freundii O22 (strain PCM 1555) was degraded under mild acidic conditions and the O-polysaccharide released was isolated by gel chromatography. Sugar and methylation analyses along with 1H- and 13C-NMR spectroscopy, including two-dimensional 1H,1H ROESY and 1H,13C HMBC experiments, showed that the repeating unit of the O-polysaccharide has the following structure:

  a-Abep(1
         |
         3
->2)-a-D-Manp-(1->4)-a-L-Rhap-(1->3)-a-D-Galp-(1->

where Abe is abequose (3,6-dideoxy-D-xylo-hexose). SDS-PAGE and immunoblotting revealed that the O-antigen of C. freundii O22 is serologically identical to those of Salmonella group B serovars (Typhimurium, Brandenburg, Sandiego, Paratyphi B) but not related to other abequose-containing O-antigens tested (Citrobacter werkmanii O38 and Salmonella Kentucky) or colitose (L enantiomer of abequose)-containing O-antigen of Escherichia coli O111.


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