Role of Fapy Glycosylase and UvrABC Excinuclease in the Repair of UVA (320‐400 nm)‐mediated DNA Damage in Escherichia coli
Journal Articles
Overview
Research
Identity
Additional Document Info
View All
Overview
abstract
Abstract— In contrast to the damage caused by far‐UV, the damage caused by UVA (320‐400 nm) is largely oxygen dependent, suggesting near‐UV‐mediated DNA damage involves reactive oxygen species. The DNA repair enzymes that recognize oxidized bases may, therefore, be an important part of the cell's near‐UV defense repertoire. To evaluate the relative importance of Fpg (Fapy) glycosylase (an enzyme known to remove oxidized bases) and the DNA damage‐inducible UvrABC excinuclease in recovery from near‐UV‐induced stress, we have constructed,fpg and uvrA derivatives of Escherichia coli and tested the response (survival) of these strains to both UVA and far‐UV radiation. Relative to control strains, the fpg‐ derivatives were found to be consistently more sensitive to the lethal effects of UVA, but not far‐UV radiation. In contrast, uvrA mutants were more sensitive than control strains to both UVA and far‐UV radiation. Thymine dimers, known to be produced by far‐UV and corrected by UvrABC, were not generated by the UVA fluences used in this study, suggesting that some other UVA‐induced lesion(s) is recognized and repaired by this excinuclease.
