Mutant Escherichia coli arginine repressor proteins that fail to bind L-arginine, yet retain the ability to bind their normal DNA-binding sites

Mol Microbiol. 1994 Aug;13(4):609-18. doi: 10.1111/j.1365-2958.1994.tb00455.x.


The Escherichia coli arginine repressor (ArgR) is an L-arginine-dependent DNA-binding protein that controls expression of the arginine biosynthetic genes and is required as an accessory protein in Xer site-specific recombination at cer and related recombination sites in plasmids. Site-directed mutagenesis was used to isolate two mutants of E. coli ArgR that were defective in arginine binding. Results from in vivo and in vitro experiments demonstrate that these mutants still act as repressors and bind their specific DNA sequences in an arginine-independent manner. Both mutants support Xer site-specific recombination at cer. One of the mutant proteins was purified and shown to bind to its DNA target sequences in vitro with different affinity and as a different molecular species to wild-type ArgR.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Arginine / biosynthesis
  • Arginine / metabolism*
  • Bacterial Proteins / genetics*
  • Bacterial Proteins / isolation & purification
  • Bacterial Proteins / metabolism*
  • Base Sequence
  • DNA, Bacterial / metabolism*
  • Enzyme Repression
  • Escherichia coli / genetics*
  • Escherichia coli Proteins*
  • Gene Expression Regulation, Bacterial
  • Genes, Bacterial / genetics
  • Molecular Sequence Data
  • Mutation
  • Nucleic Acid Conformation
  • Ornithine Carbamoyltransferase / biosynthesis
  • Protein Binding
  • Recombination, Genetic
  • Repressor Proteins / genetics*
  • Repressor Proteins / isolation & purification
  • Repressor Proteins / metabolism*


  • ArgR protein, Bacteria
  • ArgR protein, E coli
  • Bacterial Proteins
  • DNA, Bacterial
  • Escherichia coli Proteins
  • Repressor Proteins
  • Arginine
  • Ornithine Carbamoyltransferase