pBR322 plasmid DNA modified with 2-acetylaminofluorene derivatives: transforming activity and in vitro strand cleavage by the Escherichia coli uvrABC endonuclease.
AUTOR(ES)
Fuchs, R P
RESUMO
Covalently closed circular plasmid DNA was treated with three reactive derivatives of 2-acetylaminofluorene: N-acetoxy-N-2-acetylaminofluorene (N-Aco-AAF), its 7-iodo derivative (N-Aco- AAIF ) and N-hydroxy-N-2-aminofluorene (N-OH-AF), and tested as substrates for the Escherichia coli uvrABC endonuclease and for transformation frequencies on wild-type, uvrA, recA, uvrArecA and polA mutant strains. The uvrABC endonuclease reacted with all three substrates with high efficiency, implicating this enzyme in the repair of DNA containing all three types of adducts. However, only AAF- and AAIF -DNA showed greatly reduced survival on uvrA mutants (five adducts/lethal hit) relative to wild-type (20 adducts/lethal hit). AF-DNA survived equally well on uvrA mutant and wild-type cells, and at a much higher level of modification (60 adducts/lethal hit). A mutation in recA had only a minor effect on the survival of either DNA. The polA mutation reduced the survival of the AAF-treated DNA to the same extent as the uvrA mutation (five adducts/lethal hit). Also AF-DNA showed reduced survival on polA mutant cells versus wild-type. However, many more adducts (20/lethal hit) were tolerated than for AAF-DNA, indicating that AF lesions in the template do not efficiently block replication of DNA.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=557422Documentos Relacionados
- ATPase activity of the UvrA and UvrAB protein complexes of the Escherichia coli UvrABC endonuclease.
- Site-dependent cleavage of pBR322 DNA by restriction endonuclease HinfI.
- The repair of psoralen monoadducts by the Escherichia coli UvrABC endonuclease.
- Recombination between bacteriophage lambda and plasmid pBR322 in Escherichia coli.
- Protein complexes formed during the incision reaction catalyzed by the Escherichia coli UvrABC endonuclease.