Functional domains of the AraC protein.
The AraC protein, which regulates the L-arabinose operons in Escherichia coli, was dissected into two domains that function in chimeric proteins. One provides a dimerization capability and binds the ligand arabinose, and the other provides a site-specific DNA-binding capability and activates transcription. In vivo and in vitro experiments showed that a fusion protein consisting of the N-terminal half of the AraC protein and the DNA-binding domain of the LexA repressor dimerizes, binds well to a LexA operator, and represses expression of a LexA operator-beta-galactosidase fusion gene in an arabinose-responsive manner. In vivo and in vitro experiments also showed that a fusion protein consisting of the C-terminal half of the AraC protein and the leucine zipper dimerization domain from the C/EBP transcriptional activator binds to araI and activates transcription from a PBAD promoter-beta-galactosidase fusion gene. Dimerization was necessary for occupancy and activation of the wild-type AraC binding site.
Biology Department, Johns Hopkins University, Baltimore, MD 21218.
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D051777:AraC Transcription Factor; D001089:Arabinose / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins; D007700:Kinetics; D009876:Operon; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D015183:Restriction Mapping; D012697:Serine Endopeptidases; D014157:Transcription Factors; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism; D000099160:LexA Repressor Protein
D051777:AraC Transcription Factor; D001089:Arabinose; D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D012697:Serine Endopeptidases; D014157:Transcription Factors; D001616:beta-Galactosidase; D000099160:LexA Repressor Protein; C497371:AraC protein, E coli