Pasteurella multocida strains are classified into 16 Heddleston serovars based on the lipopolysaccharide (LPS) antigens expressed on the surface of the bacteria. The LPS structure and the corresponding LPS outer core biosynthesis loci of strains belonging to serovars 1, 2, 3, 5, 9 and 14, have been characterized, revealing a clear structural basis for serovar classification. However, several of these serovars are genetically related, sharing the same LPS outer core biosynthesis locus, but producing different LPS molecules as a result of mutations within LPS assembly genes. In this study we report that the P. multocida type strains belonging to serovars 8 and 13 share the same LPS outer core biosynthesis locus and produce structurally related LPS molecules. Structural analysis of the serovar 8 LPS revealed an inner core that is conserved among P. multocida strains and the following outer core structure: where X is a unique phospho-glycero moiety, 1[(4aminobutyl)amino]-3-hydroxy-1-oxopropan-2-yl hydrogen phosphate, attached to the 6 position of 1SGlcaNAc. For serovar 13, the LPS structure is the same except for the absence of the terminal phospho-glycero moiety. Analysis of the common outer core biosynthesis locus from the serovar 8 and 13 type strains identified three genes which we predict are involved in the biosynthesis of this terminal moiety. Furthermore, bioinformatic comparisons with the characterised LPS outer core glycosyltransferases from Actinobacillus pleuropneumoniae serovar 1, strain 4074, allowed us to assign a function for each of the glycosyltransferases encoded within the serovar 8/13 LPS outer core biosynthesis locus.
LPS, structure, genetics, core oligosaccharide, Pasteurella multocida
NCBI PubMed ID: 23118207Journal NLM ID: 9104124Publisher: IRL Press at Oxford University Press
Correspondence: marina.harper@monash.edu
Institutions: Australian Research Council Centre of Excellence in Structural and Functional Microbial Genomics, Department of Microbiology, Monash University, Melbourne, Australia
Methods: 13C NMR, 1H NMR, methylation, GLC-MS, de-O-acylation, SDS-PAGE, DNA techniques, 31P NMR, ESI-MS, CE-MS, sugar analyis