Identification of the recA (tif) gene product of Escherichia coli. Academic Article uri icon


MeSH Major

  • Bacterial Proteins
  • Escherichia coli
  • Genes


  • Treatments that inhibit DNA synthesis in recA(+)lexA(+)Escherichia coli stimulate synthesis of a 40,000 molecular weight protein species (protein X). The protein X molecules produced by wild-type and mutant E. coli strains have been compared by two-dimensional gel electrophoresis. One recA mutant (DM1415 spr recA1) produced a protein X with a more acidic isoelectric point than protein X from the wild type, demonstrating that protein X is probably the product of the recA gene. Additional mutants carrying the recA-linked tif-1 mutation yielded a protein X that was more basic than the wild-type protein, indicating that the tif-1 mutation also alters the recA protein. Protein X molecules from the above mutants and wild-type E. coli have been shown to yield similar partial products upon limited proteolysis in sodium dodecyl sulfate, indicating they are the same protein species. These and additional studies suggest that (i) the tif-1 mutation alters a site on the recA protein that is sensitive to DNA synthesis inhibition, (ii) synthesis of recA protein is self-regulated, and (iii) synthesis of recA protein is also regulated by the lexA product with lexA-suppressor mutations such as spr resulting in constitutive synthesis of recA protein.

publication date

  • December 1977



  • Academic Article



  • eng

PubMed Central ID

  • PMC431684

PubMed ID

  • 341152

Additional Document Info

start page

  • 5280

end page

  • 4


  • 74


  • 12