Outer membrane protein A, peptidoglycan-associated lipoprotein, and murein lipoprotein are released by Escherichia coli bacteria into serum.
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.
Hellman
J
J
Department of Infectious Diseases, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA. hellman@etherdome.mgh.harvard.edu
Loiselle
P M
PM
Tehan
M M
MM
Allaire
J E
JE
Boyle
L A
LA
Kurnick
J T
JT
Andrews
D M
DM
Sik Kim
K
K
Warren
H S
HS
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
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