Purification and characterization of a periplasmic oligopeptide binding protein from Escherichia coli.
We have purified and characterized an oligopeptide binding protein released from the periplasm of Escherichia coli W by mild osmotic shock. The purified protein was greater than 97% homogeneous as determined by either sodium dodecyl sulfate-polyacrylamide gel electrophoresis (Mr = 60,000) or isoelectric focusing (pI = 5.95). The binding protein has a Stokes radius of 30 A and a sedimentation coefficient (s(0)20,w) of 4.6 S. Based on these hydrodynamic studies, the native protein has a molecular weight of 56,000. The tripeptide, Ala-Phe-[3H]Gly, which is transported via the shock-sensitive sensitive oligopeptide permease, binds to the purified protein in dilute solution with a Kd of 0.1 microM and a stoichiometry of approximately 1 to 1. Results from this study support the hypothesis that this periplasmic oligopeptide binding protein functions in the initial recognition of peptide substrates for the oligopeptide permease system.
D001426:Bacterial Proteins / Q000302:isolation & purification* / Q000378:metabolism; D002352:Carrier Proteins / Q000302:isolation & purification* / Q000378:metabolism; D002848:Chromatography, DEAE-Cellulose; D002850:Chromatography, Gel; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins; D007700:Kinetics; D008074:Lipoproteins; D008970:Molecular Weight; D009842:Oligopeptides / Q000378:metabolism*; D011487:Protein Conformation
D001426:Bacterial Proteins; D002352:Carrier Proteins; D029968:Escherichia coli Proteins; D008074:Lipoproteins; D009842:Oligopeptides; C499290:OppA protein, E coli; C046506:oligopeptide-binding protein, bacteria