title: Purification and characterization of deacylated and/or palmitoylated lipid A species unique to Salmonella enterica serovar Typhimurium.
abstract: The Salmonella enterica serovar Typhimurium virulence gene products PhoP/PhoQ sense host microenvironments to regulate the expression of a lipid A 3-O-deacylase, PagL, and a lipid A palmitoyltransferase, PagP. Therefore, deacylation and/or palmitoylation of lipid A could occur in Salmonellae adapted to host environments. The PhoP/PhoQ-regulated modification of lipid A alters host recognition and signaling, and may play an important role in host defense against Salmonellae infection. Here we report the purification and characterization of modified lipid A species. Deacylated lipid A, deacylated and palmitoylated lipid A, and palmitoylated lipid A species were generated in Escherichia coli cells heterologously expressing salmonellae PagL and/or PagP, and then purified by sequential thin-layer chromatography. The purified lipid A species showed m/z values that correspond to single lipid A species on mass spectrometry analysis. The modified lipid A species showed reduced ability to induce cellular signaling through Toll-like receptor 4, suggesting a specific function of the lipid A modifications in the pathogenesis of salmonellae infection.
authors.affiliation: Department of Microbiology, University of Washington, Seattle, Washington, USA. kawa@nih.go.jp
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Kawasaki
authors.forename: Robert K
authors.initials: RK
authors.lastname: Ernst
authors.forename: Samuel I
authors.initials: SI
authors.lastname: Miller
mesh_terms: D000215:Acylation; D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology / Q000187:drug effects; D002460:Cell Line; D002855:Chromatography, Thin Layer; D004305:Dose-Response Relationship, Drug; D000939:Epitopes; D004926:Escherichia coli / Q000235:genetics; D017930:Genes, Reporter; D006801:Humans; D008050:Lipid A / Q000032:analysis / Q000737:chemistry* / Q000302:isolation & purification* / Q000494:pharmacology; D008156:Luciferases / Q000378:metabolism; D013058:Mass Spectrometry; D051379:Mice; D015394:Molecular Structure; D019308:Palmitic Acid / Q000737:chemistry*; D010957:Plasmids; D016133:Polymerase Chain Reaction; D012486:Salmonella typhimurium / Q000737:chemistry* / Q000145:classification; D012703:Serotyping
chemical_list: D000939:Epitopes; D008050:Lipid A; D019308:Palmitic Acid; D008156:Luciferases