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Journal of Bacteriology, April 2002, p. 2100-2107, Vol. 184, No. 8
0021-9193/02/$04.00+0 DOI: 10.1128/JB.184.8.2100-2107.2002
Copyright © 2002, American Society for Microbiology. All Rights Reserved.
Anthony P. Moran,2 Lorna A. Millar,1 Martina M. Prendergast,2 and Julian M. Ketley1*
Department of Genetics, University of Leicester, Leicester, United Kingdom,1 Department of Microbiology, University College, Galway, Ireland2
Received 3 August 2001/ Accepted 10 December 2001
Campylobacter jejuni produces both lipooligosaccharide (LOS) and a higher-molecular-weight polysaccharide that is believed to form a capsule. The role of these surface polysaccharides in C. jejuni-mediated enteric disease is unclear; however, epitopes associated with the LOS are linked to the development of neurological complications. In Escherichia coli and Salmonella enterica serovar Typhimurium the waaF gene encodes a heptosyltransferase, which catalyzes the transfer of the second L-glycero-D-manno-heptose residue to the core oligosaccharide moiety of lipopolysaccharide (LPS), and mutation of waaF results in a truncated core oligosaccharide. In this report we confirm experimentally that C. jejuni gene Cj1148 encodes the heptosyltransferase II enzyme, WaaF. The Campylobacter waaF gene complements an S. enterica serovar Typhimurium waaF mutation and restores the ability to produce full-sized lipopolysaccharide. To examine the role of WaaF in C. jejuni, waaF mutants were constructed in strains NCTC 11168 and NCTC 11828. Loss of heptosyltransferase activity resulted in the production of a truncated core oligosaccharide, failure to bind specific ligands, and loss of serum reactive GM1, asialo-GM1, and GM2 ganglioside epitopes. The mutation of waaF did not affect the higher-molecular-weight polysaccharide supporting the production of a LOS-independent capsular polysaccharide by C. jejuni. The exact structural basis for the truncation of the core oligosaccharide was verified by comparative chemical analysis. The NCTC 11168 core oligosaccharide differs from that known for HS:2 strain CCUG 10936 in possessing an extra terminal disaccharide of galactose-ß(1,3) N-acetylgalactosamine. In comparison, the waaF mutant possessed a truncated molecule consistent with that observed with waaF mutants in other bacterial species.
Present address: Molecular Bacteriology and Immunology Group, Division of Microbiology, Queens Medical Centre, University of Nottingham, Nottingham NG7 2UH, United Kingdom.
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