Functional assay of Salmonella typhi OmpC using reconstituted large unilamellar vesicles: a general method for characterization of outer membrane proteins.
The immunodominant trimeric beta-barrel outer membrane protein OmpC from Salmonella typhi, the causative agent of typhoid, has been functionally characterized here. The activity in the vesicle environment was studied in vitro using OmpC reconstituted into proteoliposomes. Passage of polysaccharides and polyethyleneglycols through OmpC has been examined to determine the permeability properties. The relative rate of neutral solute flux yields a radius of 1.1 nm for the S. typhi OmpC pore. This is almost double the pore size of Escherichia coli. This provides an example of large pore size present in the porins that form trimers as in the general bacterial porin family. The method used in this study provides a good membrane model for functional studies of porins.
Sundara Baalaji
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Center of Excellence in Bioinformatics, School of Biotechnology, Madurai-Kamaraj University, Palkalainagar, Madurai 625021, India.
Mathew
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MK
Krishnaswamy
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S
D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry / Q000378:metabolism*; D004926:Escherichia coli / Q000378:metabolism; D009844:Oligosaccharides / Q000378:metabolism; D011092:Polyethylene Glycols / Q000378:metabolism; D018272:Porins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D011510:Proteolipids / Q000378:metabolism; D012485:Salmonella typhi / Q000378:metabolism*; D013997:Time Factors; D053835:Unilamellar Liposomes / Q000378:metabolism*
D001425:Bacterial Outer Membrane Proteins; D009844:Oligosaccharides; C113724:OmpC protein; D018272:Porins; D011510:Proteolipids; D053835:Unilamellar Liposomes; C020485:proteoliposomes; D011092:Polyethylene Glycols