Department of Biochemistry and Molecular Pharmacology
Antibiotics, Antineoplastic; Bacterial Proteins; Bleomycin; Culture Media; DNA Breaks, Double-Stranded; DNA Ligases; DNA Restriction Enzymes; DNA, Bacterial; DNA-(Apurinic or Apyrimidinic Site) Lyase; Drug Resistance, Bacterial; Escherichia coli K12; Escherichia coli Proteins; Genes, Bacterial; Mutation; Oligonucleotide Array Sequence Analysis; RNA, Bacterial; Recombinational DNA Repair; SOS Response (Genetics)
Biochemistry, Biophysics, and Structural Biology | Life Sciences | Medicine and Health Sciences
Bleomycin (BLM) is a glycopeptide antibiotic and anti-tumor agent that targets primarily the furanose rings of DNA and in the presence of ferrous ions produces oxidative damage and DNA strand breaks. Escherichia coli cells growing in broth medium and exposed to low concentrations of BLM contain double-strand breaks and require homologous recombination to survive. To a lesser extent, the cells also require the abasic (AP) endonucleases associated with base excision repair, presumably to repair oxidative damage. As expected, there is strong induction of the SOS system in treated cells. In contrast, E. coli cells growing in glucose or glycerol minimal medium are resistant to the lethal action of BLM and do not require either homologous recombination functions or AP-endonucleases for survival. DNA ligase activity, however, is needed for cells growing in minimal medium to resist the lethal effects of BLM. There is weak SOS induction in such treated cells.