Peptidoglycan associated lipoprotein (Pal) of Escherichia coli (E. coli) is a characteristic bacterial lipoprotein, with an N-terminal lipid moiety anchoring it to the outer membrane. Since its discovery over three decades ago, Pal has been well studied for its participation in the TolPal complex which spans the periplasm and has been proposed to play important roles in bacterial survival, pathogenesis and virulence. Previous studies of Pal place the lipoprotein in the periplasm of E. coli, allowing it to interact with Tol proteins and the peptidoglycan layer. Here, we describe for the first time, a subpopulation of Pal which is present on the cell surface of E. coli. Flow cytometry and confocal microscopy detect anti-Pal antibodies on the surface of intact E. coli cells. Interestingly, Pal is surface exposed in an 'all or nothing' manner, such that most of the cells contain only internal Pal, with fewer cells (,20 %) exhibiting surface Pal.
Peptidoglycan associated lipoprotein (Pal) is an outer membrane protein from Gram‐negative bacteria, including Escherichia coli (E. coli). E. coli has two subpopulations of Pal: a periplasmic subpopulation bound to peptidoglycan and a surface exposed subpopulation. When the bacteria are cultured under normal conditions in rich media, only a small percentage of cells contain surface exposed Pal. Under more stressful culture conditions (ex. increased temperature, the presence of antibiotics), E. coli will release outer membrane vesicles (OMVs). Using ultracentrifugation and immunoblotting, we have shown that Pal is released from E. coli in these OMV's. We also used flow cytometry to measure the surface exposed Pal subpopulations in hyper‐vesiculating E. coli cells and their OMVs. Preliminary data suggest that the surface exposed Pal subpopulations are increased in vesiculating cells and OMVs.Support or Funding InformationReceived: Rochester Institute of Technology FEAD grant to Dr. Lea Vacca Michel Applying for: RIT Honors program $500 travel stipend to Nicole Pannullo Applying for: RIT National Technical Institute for the Deaf Student Travel Award to Nicole PannulloThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
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