title: Bordetella parapertussis PagP mediates the addition of two palmitates to the lipopolysaccharide lipid A.
abstract: Bordetella bronchiseptica PagP (PagPBB) is a lipid A palmitoyl transferase that is required for resistance to antibody-dependent complement-mediated killing in a murine model of infection. B. parapertussis contains a putative pagP homolog (encoding B. parapertussis PagP [PagPBPa]), but its role in the biosynthesis of lipid A, the membrane anchor of lipopolysaccharide (LPS), has not been investigated. Mass spectrometry analysis revealed that wild-type B. parapertussis lipid A consists of a heterogeneous mixture of lipid A structures, with penta- and hexa-acylated structures containing one and two palmitates, respectively. Through mutational analysis, we demonstrate that PagPBPa is required for the modification of lipid A with palmitate. While PagPBB transfers a single palmitate to the lipid A C-3' position, PagPBPa transfers palmitates to the lipid A C-2 and C-3' positions. The addition of two palmitate acyl chains is unique to B. parapertussis. Mutation of pagPBPa resulted in a mutant strain with increased sensitivity to antimicrobial peptide killing and decreased endotoxicity, as evidenced by reduced proinflammatory responses via Toll-like receptor 4 (TLR4) to the hypoacylated LPS. Therefore, PagP-mediated modification of lipid A regulates outer membrane function and may be a means to modify interactions between the bacterium and its human host during infection.
authors.affiliation: Department of Microbial Pathogenesis, University of Maryland School of Dentistry, Baltimore, Maryland, USA.
authors.forename: L E
authors.initials: LE
authors.lastname: Hittle
authors.affiliation: Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland, USA.
authors.forename: J W
authors.initials: JW
authors.lastname: Jones
authors.affiliation: Department of Comparative Medicine, School of Medicine, University of Washington, Seattle, Washington, USA.
authors.forename: A M
authors.initials: AM
authors.lastname: Hajjar
authors.affiliation: Department of Microbial Pathogenesis, University of Maryland School of Dentistry, Baltimore, Maryland, USA rkernst@umaryland.edu a.preston@bath.ac.uk.
authors.forename: R K
authors.initials: RK
authors.lastname: Ernst
authors.affiliation: Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom rkernst@umaryland.edu a.preston@bath.ac.uk.
authors.forename: A
authors.initials: A
authors.lastname: Preston
mesh_terms: D000217:Acyltransferases / Q000235:genetics / Q000378:metabolism*; D042483:Bordetella parapertussis / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics; D004252:DNA Mutational Analysis; D008050:Lipid A / Q000737:chemistry / Q000378:metabolism*; D013058:Mass Spectrometry; D010168:Palmitates / Q000378:metabolism*
chemical_list: D008050:Lipid A; D010168:Palmitates; D000217:Acyltransferases