Amino acid-mediated induction of the basic amino acid-specific outer membrane porin OprD from Pseudomonas aeruginosa.
Pseudomonas aeruginosa can utilize arginine and other amino acids as both carbon and nitrogen sources. Earlier studies have shown that the specific porin OprD facilitates the diffusion of basic amino acids as well as the structurally analogous beta-lactam antibiotic imipenem. The studies reported here showed that the expression of OprD was strongly induced when arginine, histidine, glutamate, or alanine served as the sole source of carbon. The addition of succinate exerted a negative effect on induction of oprD, likely due to catabolite repression. The arginine-mediated induction was dependent on the regulatory protein ArgR, and binding of purified ArgR to its operator upstream of the oprD gene was demonstrated by gel mobility shift and DNase assays. The expression of OprD induced by glutamate as the carbon source, however, was independent of ArgR, indicating the presence of more than a single activation mechanism. In addition, it was observed that the levels of OprD responded strongly to glutamate and alanine as the sole sources of nitrogen. Thus, that the expression of oprD is linked to both carbon and nitrogen metabolism of Pseudomonas aeruginosa.
Ochs
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Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada.
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Hancock
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Abdelal
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D000596:Amino Acids / Q000378:metabolism*; D001426:Bacterial Proteins / Q000378:metabolism; D001483:Base Sequence; D001665:Binding Sites; D002244:Carbon; D003470:Culture Media; D004269:DNA, Bacterial; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D009584:Nitrogen; D009875:Operator Regions, Genetic; D018272:Porins / Q000096:biosynthesis* / Q000235:genetics; D011550:Pseudomonas aeruginosa / Q000235:genetics / Q000378:metabolism*; D012097:Repressor Proteins / Q000378:metabolism; D014158:Transcription, Genetic
D000596:Amino Acids; C087018:ArgR protein, Bacteria; D001426:Bacterial Proteins; D003470:Culture Media; D004269:DNA, Bacterial; D018272:Porins; D012097:Repressor Proteins; C077157:OprD protein, Pseudomonas aeruginosa; D002244:Carbon; D009584:Nitrogen