uvrB gene deletion enhances SOS chromotest sensitivity for nitroreductases that preferentially generate the 4-hydroxylamine metabolite of the anti-cancer prodrug CB1954

J Biotechnol. 2010 Oct 1;150(1):190-4. doi: 10.1016/j.jbiotec.2010.08.007. Epub 2010 Aug 19.


CB1954 is an anti-cancer prodrug that can be reduced at either of two nitro groups to form cytotoxic metabolites. We describe here two efficient and previously uncharacterized nitroreductases, YfkO from Bacillus subtilis which reduces CB1954 exclusively at the 4-NO(2) position, and NfsA from Klebsiella pneumoniae which preferentially reduces the 2-NO(2) group. Utilizing these novel enzymes, together with three previously characterized nitroreductases, we demonstrate that the Escherichia coli SOS-chromotest assay can differentially detect the 4-nitro versus 2-nitro reduction products of CB1954 following deletion of the nucleotide excision repair gene uvrB, but not mismatch repair (mutS) or methyltransferase (ada/ogt) genes. These findings may hold significance for identification and selection of nitroreductases for CB1954-mediated gene therapy, particularly when targeting tumors that are deficient in nucleotide excision repair. Moreover, we demonstrate that comparative SOS chromotest analysis in wild type and uvrB mutant strains can be used to determine whether or not nucleotide excision repair plays a significant role in processing DNA damage resulting from activation of different nitroaromatic prodrugs.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antineoplastic Agents / chemistry
  • Antineoplastic Agents / metabolism*
  • Aziridines / chemistry
  • Aziridines / metabolism*
  • Bacillus subtilis / enzymology
  • Bacillus subtilis / genetics
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • DNA Helicases / genetics*
  • DNA Helicases / metabolism
  • Escherichia coli Proteins / genetics*
  • Escherichia coli Proteins / metabolism
  • Gene Deletion*
  • Kinetics
  • Klebsiella pneumoniae / enzymology
  • Klebsiella pneumoniae / genetics
  • Metronidazole
  • Molecular Conformation
  • Molecular Sequence Data
  • Nitrofurazone
  • Nitroreductases
  • SOS Response, Genetics / genetics*


  • Antineoplastic Agents
  • Aziridines
  • Bacterial Proteins
  • Escherichia coli Proteins
  • UvrB protein, E coli
  • Metronidazole
  • tretazicar
  • Nitroreductases
  • DNA Helicases
  • Nitrofurazone

Associated data

  • GENBANK/GU726295
  • GENBANK/GU726296