title: Outer membrane protein A, peptidoglycan-associated lipoprotein, and murein lipoprotein are released by Escherichia coli bacteria into serum.
abstract: Complexes containing lipopolysaccharide (LPS) and three outer membrane proteins (OMPs) are released by gram-negative bacteria incubated in human serum and into the circulation in an experimental model of sepsis. The same OMPs are bound by immunoglobulin G (IgG) in the cross-protective antiserum raised to Escherichia coli J5 (anti-J5 IgG). This study was performed to identify the three OMPs. The 35-kDa OMP was identified as outer membrane protein A (OmpA) by immunoblotting studies using OmpA-deficient bacteria and recombinant OmpA protein. The 18-kDa OMP was identified as peptidoglycan-associated lipoprotein (PAL) based on peptide sequences from the purified protein and immunoblotting studies using PAL-deficient bacteria. The 5- to 9-kDa OMP was identified as murein lipoprotein (MLP) based on immunoblotting studies using MLP-deficient bacteria. The studies identify the OMPs released into human serum and into the circulation in an experimental model of sepsis as OmpA, PAL, and MLP.
authors.affiliation: Department of Infectious Diseases, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA. hellman@etherdome.mgh.harvard.edu
authors.forename: J
authors.initials: J
authors.lastname: Hellman
authors.forename: P M
authors.initials: PM
authors.lastname: Loiselle
authors.forename: M M
authors.initials: MM
authors.lastname: Tehan
authors.forename: J E
authors.initials: JE
authors.lastname: Allaire
authors.forename: L A
authors.initials: LA
authors.lastname: Boyle
authors.forename: J T
authors.initials: JT
authors.lastname: Kurnick
authors.forename: D M
authors.initials: DM
authors.lastname: Andrews
authors.forename: K
authors.initials: K
authors.lastname: Sik Kim
authors.forename: H S
authors.initials: HS
authors.lastname: Warren
mesh_terms: D000818:Animals; D001425:Bacterial Outer Membrane Proteins / Q000032:analysis* / Q000276:immunology; D004926:Escherichia coli / Q000737:chemistry* / Q000378:metabolism; D029968:Escherichia coli Proteins; D006801:Humans; D008074:Lipoproteins / Q000032:analysis* / Q000276:immunology; D010457:Peptidoglycan / Q000032:analysis* / Q000276:immunology; D011509:Proteoglycans; D011817:Rabbits
chemical_list: D001425:Bacterial Outer Membrane Proteins; D029968:Escherichia coli Proteins; C031163:ExcC protein, E coli; D008074:Lipoproteins; D010457:Peptidoglycan; D011509:Proteoglycans; C069988:PplA protein, Legionella pneumophila; C078167:OMPA outer membrane proteins