A genetic analysis of various functions of the TyrR protein of Escherichia coli.
The TyrR protein is involved in both repression and activation of the genes of the TyrR regulon. Correction of an error in a previously published sequence has revealed a Cro-like helix-turn-helix DNA-binding domain near the carboxyl terminus. Site-directed mutagenesis in this region has generated a number of mutants that can no longer repress or activate. Deletions of amino acid residues 5 to 42 produced a protein that could repress but not activate. The central domain of TyrR contains an ATP-binding site and is homologous with the NtrC family of activator proteins. A mutation to site A of the ATP-binding site and other mutations in this region affect tyrosine-mediated repression but do not prevent activation or phenylalanine-mediated repression of aroG.
Yang
J
J
Department of Microbiology, University of Melbourne, Parkville, Victoria, Australia.
Ganesan
S
S
Sarsero
J
J
Pittard
A J
AJ
D000595:Amino Acid Sequence; D001483:Base Sequence; D004269:DNA, Bacterial; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins; D005816:Genetic Complementation Test; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D011487:Protein Conformation; D012097:Repressor Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; C069256:TyrR protein, E coli