title: A novel secondary acyl chain in the lipopolysaccharide of Bordetella pertussis required for efficient infection of human macrophages.
abstract: Lipopolysaccharide is one of the major constituents of the Gram-negative bacterial outer membrane and is a potent stimulator of the host innate immune response. The biosynthesis of the lipid A moiety of lipopolysaccharide is a complex process in which multiple gene products are involved. Two late lipid A acyl transferases, LpxL and LpxM, were first identified in Escherichia coli and shown to be responsible for the addition of secondary acyl chains to the 2' and 3' positions of lipid A, respectively. Here, we describe the identification of two lpxL homologues in the genome of Bordetella pertussis. We show that one of them, LpxL2, is responsible for the addition of the secondary myristate group that is normally present at the 2' position of B. pertussis lipid A, whereas the other one, LpxL1, mediates the addition of a previously unrecognized secondary 2-hydroxy laurate at the 2 position. Increased expression of lpxL1 results in the appearance of a hexa-acylated lipopolysaccharide form with strongly increased endotoxic activity. In addition, we show that an lpxL1-deficient mutant of B. pertussis displays a defect in the infection of human macrophages.
authors.affiliation: Department of Molecular Microbiology, Utrecht University, Padualaan 8, Utrecht, The Netherlands.
authors.forename: Jeroen
authors.initials: J
authors.lastname: Geurtsen
authors.forename: Eline
authors.initials: E
authors.lastname: Angevaare
authors.forename: Marlieke
authors.initials: M
authors.lastname: Janssen
authors.forename: Hendrik-Jan
authors.initials: HJ
authors.lastname: Hamstra
authors.forename: Jan
authors.initials: J
authors.lastname: ten  Hove
authors.forename: Alex
authors.initials: A
authors.lastname: de Haan
authors.forename: Betsy
authors.initials: B
authors.lastname: Kuipers
authors.forename: Jan
authors.initials: J
authors.lastname: Tommassen
authors.forename: Peter
authors.initials: P
authors.lastname: van der Ley
mesh_terms: D000942:Antigens, Bacterial / Q000737:chemistry; D001886:Bordetella pertussis / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004926:Escherichia coli / Q000378:metabolism; D005816:Genetic Complementation Test; D006801:Humans; D015850:Interleukin-6 / Q000378:metabolism; D008055:Lipids / Q000737:chemistry; D008070:Lipopolysaccharides / Q000378:metabolism*; D008264:Macrophages / Q000378:metabolism* / Q000382:microbiology*; D013058:Mass Spectrometry; D008954:Models, Biological; D008956:Models, Chemical; D010957:Plasmids / Q000378:metabolism; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D000942:Antigens, Bacterial; D015850:Interleukin-6; D008055:Lipids; D008070:Lipopolysaccharides