Influence of DNA adenine methylase on the sensitivity of Escherichia coli to near-ultraviolet radiation and hydrogen peroxide.
Near-ultraviolet (NUV) radiation and hydrogen peroxide (H2O2) inactivation studies were performed on Escherichia coli K-12 DNA adenine methylation (dam) mutants and on cells that carry plasmids which overexpress Dam methylase. Lack of methylation resulted in increased sensitivity to NUV and H2O2 (a photoproduct of NUV). In a dam mutant carrying a dam plasmid, the levels of Dam enzyme and resistance to NUV and H2O2 were restored. However, using a multicopy dam+ plasmid strain, increasing the methylase above wildtype levels resulted in an increase in sensitivity of the cells rather than resistance.
Division of Biological Sciences, University of Missouri, Columbia 65211.
P
P
Yallaly
A
A
Eisenstark
D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology* / Q000528:radiation effects; D006861:Hydrogen Peroxide / Q000633:toxicity*; D010957:Plasmids; D015265:Site-Specific DNA-Methyltransferase (Adenine-Specific) / Q000502:physiology*; D014466:Ultraviolet Rays / Q000009:adverse effects*
D006861:Hydrogen Peroxide; D015265:Site-Specific DNA-Methyltransferase (Adenine-Specific)