Sensitivity of polA mutants of Escherichia coli K-12 to ozone and radiations.

Different polA mutants of Escherichia coli K-12 were exposed to ozone, X-rays and UV radiation, in order to compare the role of the various enzymatic activities of DNA polymerase I in the repair of damage caused by these agents. As was the case with radiations, the polymerase-deficient mutants were the most sensitive to ozone, followed by the 5'-3' exonuclease-deficient mutants. The 3'-5' exonuclease activity of pol I appeared to play a minor role in the repair of damage induced by all these agents.