National Research Council Canada (NRC-CNRC); NRC Institute for Biological Sciences

English

Article

Infection and Immunity

2009

1532-1542

BOYCE2009

15459208

Lipopolysaccharide; Pasteurella multocida; virulence; Mass spectrometry

We previously determined the structure of the Pasteurella multocida Heeleston type 1 lipopolysaccharide (LPS) molecule and characterized some of the transferases essential for LPS biosythesis. We also showed that P. multocida strains expressing truncated LPS display reduced virulence. Here we have identified all the remaining glycosyltransferases required for synthesis of the oligosaccharide extension of the P. multocida Heddleston type 1 LPS, including a novel α-1,6 glucosyltransferase, a β-1,4 glucosyltransferase, a putative bi-functional galactosyltransferase and two heptosyltransferases. In addition, we identified a novel oligosaccharide extension expressed only in a heptosyltransferase (hptE) mutant background. All of the analyzed mutants expressing LPS with a truncated main oligosaccharide extension displayed reduced virulence but those expressing LPS with an intact heptose side chain were able to persist for long periods in muscle tissue. The hptC mutant, which expressed LPS with the shortest oligosaccharide extension and no heptose side chain, was unable to persist on the muscle or cause any disease. Furthermore, all of the mutants displayed inclreased sensitivity to the chicken antimicrobial peptide fowlicidin-1, with mutants expressing highly truncated LPS the most sensitive.