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Journal of Endotoxin Research, Vol. 5, No. 1-2,
96-101 (1999)
DOI: 10.1177/09680519990050011001
© 1999 SAGE Publications
Glycosyltransferases of Pseudomonas aeruginosa that assemble the O antigens of A band and B band lipopolysaccharide
J.S. Lam
Canadian Bacterial Diseases Network, Department of Microbiology, University of Guelph, Guelph, Ontario, Canada, jlam{at}uoguelph.ca
H.L. Rocchetta
Canadian Bacterial Diseases Network, Department of Microbiology, University of Guelph, Guelph, Ontario, Canada
L.L. Burrows
Canadian Bacterial Diseases Network, Department of Microbiology, University of Guelph, Guelph, Ontario, Canada
Pseudomonas aeruginosa produces two forms of lipopolysaccharide (LPS) designated A band and B band. The O-polysaccharide region of A band is a conserved D-rhamnan polymer arranged 12, 13, 13, while B band is serotype-specific with differences in the O-antigenic region dividing P. aeruginosa into 20 stereotypes. The B band O-antigen unit of serotype O5 is [4)-ß-D-Man(2NAc3N)A-(1-4)-ß-D-Man(2NAc3NAc)A-(1-3)- -D-Fuc2NAc]. The glycosidic structure of LPS molecules specified by the action of dedicated glycosyltransferases. The wbp clusters of A band and B band (serotype O5) were each found to contain three genes coding for putative glycosyltransferases: wbpX, wbpY, wbpZ, and wbpH, wbpJ, wbpL , respectively. To examine the role of these potential transferases in LPS assembly, chromosomal mutations were generated within all 6 genes. LPS analysis reveals that wbpX, wbpY, and wbpZ mutants express an AB+ phenotype, while wbpH and wbpJ mutants are A+B. Interestingly, mutations in wbpL, an Escherichia coli wec A homologue, abrogates both A band and B band LPS synthesis. Based on amino acid homologies, O-polysaccharide structures and LPS phenotypes of transferase mutants, we propose an assembly scheme for these two LPS molecules.

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