PMID:7929058
| Citation |
Choi, KY, Lu, F and Zalkin, H (1994) Mutagenesis of amino acid residues required for binding of corepressors to the purine repressor. J. Biol. Chem. 269:24066-72 |
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| Abstract |
The corepressor-binding domain of the Escherichia coli purine repressor (PurR) is homologous with several periplasmic sugar-binding proteins. Four amino acids in PurR were investigated for a role in binding of corepressors. Three of the residues, Asp146, Arg196 and Asp275, are conserved in periplasmic binding proteins for ribose, glucose/galactose, and arabinose and function to bind sugars. A fourth amino acid, Trp147, required for corepressor binding to PurR, corresponds to residues in glucose/galactose, ribose, and arabinose that also have a role in sugar binding. The four mutations that were constructed perturbed the binding of both hypoxanthine and guanine thus providing evidence for a single corepressor site/PurR subunit. The decreased corepressor binding affinity resulted in reduced affinity of mutant repressors for operator DNA in vitro and decreased capacity for repression in vivo. The corepressor-binding site in PurR appears to be similar to the conserved ligand-binding sites in the three periplasmic sugar-binding proteins and in the LacI family of repressors. |
| Links | |
| Keywords |
Amino Acids/genetics; Amino Acids/metabolism; Bacterial Proteins/genetics; Bacterial Proteins/isolation & purification; Bacterial Proteins/metabolism; Base Sequence; DNA, Recombinant; DNA-Binding Proteins/genetics; DNA-Binding Proteins/isolation & purification; DNA-Binding Proteins/metabolism; Escherichia coli Proteins; Molecular Sequence Data; Mutagenesis, Site-Directed; Operator Regions, Genetic; Protein Binding; Repressor Proteins/genetics; Repressor Proteins/isolation & purification; Repressor Proteins/metabolism |
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