Identification and characterization of dppA, an Escherichia coli gene encoding a periplasmic dipeptide transport protein.
We describe the isolation and analysis of an Escherichia coli gene, dppA, and its role in dipeptide transport. dppA maps near min 79 and encodes a protein (DppA) that has regions of amino acid similarity with a peptide-binding protein from Salmonella typhimurium (OppA). Like OppA, DppA is found in the periplasmic space and thus is most likely a dipeptide-binding protein. Insertional inactivation of dppA results in the inability of a proline auxotroph to utilize Pro-Gly as a proline source. dppA-dependent Pro-Gly utilization does not require any of the three major proline transport systems, demonstrating that DppA is not simply a dipeptidase. An in vivo competition assay was used to show that DppA is probably involved in the transport of dipeptides other than Pro-Gly. Transcription of dppA is repressed by the presence of casamino acids, suggesting that the cell alters its dipeptide transport capabilities in response to an environmental signal.
Olson
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Molecular Biology Research, Upjohn Company, Kalamazoo, Michigan 49007.
Dunyak
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Jurss
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Poorman
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D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics*; D010582:Bacteriophage lambda / Q000235:genetics; D001483:Base Sequence; D001692:Biological Transport; D015152:Blotting, Northern; D002352:Carrier Proteins / Q000235:genetics*; D004269:DNA, Bacterial / Q000235:genetics / Q000302:isolation & purification; D004926:Escherichia coli / Q000235:genetics* / Q000254:growth & development; D029968:Escherichia coli Proteins; D005798:Genes, Bacterial; D026901:Membrane Transport Proteins / Q000235:genetics*; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D015345:Oligonucleotide Probes; D033902:Periplasmic Binding Proteins; D010957:Plasmids; D012329:RNA, Bacterial / Q000235:genetics / Q000302:isolation & purification; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid
D001426:Bacterial Proteins; D002352:Carrier Proteins; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D026901:Membrane Transport Proteins; D015345:Oligonucleotide Probes; D033902:Periplasmic Binding Proteins; D012329:RNA, Bacterial; C066768:dppA protein, E coli; C037230:oligopeptide permease, Bacteria