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Pasteurella multocida Expresses Two Lipopolysaccharide Glycoforms Simultaneously, but Only a Single Form Is Required for Virulence: Identification of Two Acceptor-Specific Heptosyl I Transferases

Harper, M. and Boyce, J.D. and Cox, A.D. and St. Michael, F. and Wilke, I.W. and Blackall, P.J. and Adler, B. (2007) Pasteurella multocida Expresses Two Lipopolysaccharide Glycoforms Simultaneously, but Only a Single Form Is Required for Virulence: Identification of Two Acceptor-Specific Heptosyl I Transferases. Infection and Immunity, 75 (8). pp. 3885-3893.

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Article Link(s): http://dx.doi.org/10.1128/IAI.00212-07

Publisher URL: http://www.asm.org/

Abstract

Lipopolysaccharide (LPS) is a critical virulence determinant in Pasteurella multocida and a major antigen responsible for host protective immunity. In other mucosal pathogens, variation in LPS or lipooligosaccharide structure typically occurs in the outer core oligosaccharide regions due to phase variation. P. multocida elaborates a conserved oligosaccharide extension attached to two different, simultaneously expressed inner core structures, one containing a single phosphorylated 3-deoxy-D-manno-octulosonic acid (Kdo) residue and the other containing two Kdo residues. We demonstrate that two heptosyltransferases, HptA and HptB, add the first heptose molecule to the Kdo1 residue and that each exclusively recognizes different acceptor molecules. HptA is specific for the glycoform containing a single, phosphorylated Kdo residue (glycoform A), while HptB is specific for the glycoform containing two Kdo residues (glycoform B). In addition, KdkA was identified as a Kdo kinase, required for phosphorylation of the first Kdo molecule. Importantly, virulence data obtained from infected chickens showed that while wild-type P. multocida expresses both LPS glycoforms in vivo, bacterial mutants that produced only glycoform B were fully virulent, demonstrating for the first time that expression of a single LPS form is sufficient for P. multocida survival in vivo. We conclude that the ability of P. multocida to elaborate alternative inner core LPS structures is due to the simultaneous expression of two different heptosyltransferases that add the first heptose residue to the nascent LPS molecule and to the expression of both a bifunctional Kdo transferase and a Kdo kinase, which results in the initial assembly of two inner core structures.

Item Type:Article
Corporate Creators:Animal Science
Additional Information:© American Society for Microbiology.
Keywords:Actinobacillus pleuropneumoniae serotype 1; Neisseria meningitidis; core oligosaccharides; structural analysis; heptosyltransferase mutant; antimicrobial peptides; biosynthesis; gene; endotoxins; chickens.
Subjects:Veterinary medicine > Veterinary bacteriology
Deposited On:20 Jan 2009 06:23
Last Modified:09 Sep 2010 05:27

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