Publications

• Transfer of palmitate from phospholipids to lipid A in outer membranes of gram-negative bacteria.

  Bishop R.E., Gibbons H.S., Guina T., Trent M.S., Miller S.I., Raetz C.R.

  Regulated covalent modifications of lipid A are implicated in virulence of pathogenic Gram-negative bacteria. The Salmonella typhimurium PhoP/PhoQ-activated gene pagP is required both for biosynthesis of hepta-acylated lipid A species containing palmitate and for resistance to cationic anti-microb ... >> More

  Regulated covalent modifications of lipid A are implicated in virulence of pathogenic Gram-negative bacteria. The Salmonella typhimurium PhoP/PhoQ-activated gene pagP is required both for biosynthesis of hepta-acylated lipid A species containing palmitate and for resistance to cationic anti-microbial peptides. Palmitoylated lipid A can also function as an endotoxin antagonist. We now show that pagP and its Escherichia coli homolog (crcA) encode an unusual enzyme of lipid A biosynthesis localized in the outer membrane. PagP transfers a palmitate residue from the sn-1 position of a phospholipid to the N-linked hydroxymyristate on the proximal unit of lipid A (or its precursors). PagP bearing a C-terminal His(6)-tag accumulated in outer membranes during overproduction, was purified with full activity and was shown by cross-linking to behave as a homodimer. PagP is the first example of an outer membrane enzyme involved in lipid A biosynthesis. Additional pagP homologs are encoded in the genomes of Yersinia and Bordetella species. PagP may provide an adaptive response toward both Mg(2+) limitation and host innate immune defenses. << Less

  EMBO J. 19:5071-5080(2000) [PubMed] [EuropePMC]

  This publication is cited by 5 other entries.

• PagP crystallized from SDS/cosolvent reveals the route for phospholipid access to the hydrocarbon ruler.

  Cuesta-Seijo J.A., Neale C., Khan M.A., Moktar J., Tran C.D., Bishop R.E., Pomes R., Prive G.G.

  Enzymatic reactions involving bilayer lipids occur in an environment with strict physical and topological constraints. The integral membrane enzyme PagP transfers a palmitoyl group from a phospholipid to lipid A in order to assist Escherichia coli in evading host immune defenses during infection. ... >> More

  Enzymatic reactions involving bilayer lipids occur in an environment with strict physical and topological constraints. The integral membrane enzyme PagP transfers a palmitoyl group from a phospholipid to lipid A in order to assist Escherichia coli in evading host immune defenses during infection. PagP measures the palmitoyl group with an internal hydrocarbon ruler that is formed in the interior of the eight-stranded antiparallel β barrel. The access and egress of the palmitoyl group is thought to take a lateral route from the bilayer phase to the barrel interior. Molecular dynamics, mutagenesis, and a 1.4 A crystal structure of PagP in an SDS / 2-methyl-2,4-pentanediol (MPD) cosolvent system reveal that phospholipid access occurs at the crenel present between strands F and G of PagP. In this way, the phospholipid head group can remain exposed to the cell exterior while the lipid acyl chain remains in a predominantly hydrophobic environment as it translocates to the protein interior. << Less

  Structure 18:1210-1219(2010) [PubMed] [EuropePMC]

  This publication is cited by 5 other entries.