Substrate specificity of the Escherichia coli 4-aminobutyrate carrier encoded by gabP. Uptake and counterflow of structurally diverse molecules.
Transport of 4-aminobutyrate into Escherichia coli is catalyzed by gab permease (GabP). Although published studies show that GabP is relatively specific, recognizing the common alpha-amino acids with low affinity, recent work from this laboratory indicates that a number of synthetic compounds are high affinity transport inhibitors (50% inhibition at 5-100 microM). Here we present evidence that many of these structurally heterogeneous compounds not only inhibit transport but also function as alternative GabP substrates (i.e. a set of observations inconsistent with the idea that the core of the GabP transport channel exhibits rigid structural specificity for the native substrate, 4-aminobutyrate.
Brechtel
C E
CE
Department of Physiology and Biophysics, University of Texas Medical Branch, Galveston 77555-0641, USA.
Hu
L
L
King
S C
SC
D000613:Aminobutyrates / Q000378:metabolism*; D001692:Biological Transport; D002352:Carrier Proteins / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D004926:Escherichia coli / Q000378:metabolism*; D051268:GA-Binding Protein Transcription Factor; D026901:Membrane Transport Proteins / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism
D000613:Aminobutyrates; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D051268:GA-Binding Protein Transcription Factor; D026901:Membrane Transport Proteins; D014157:Transcription Factors