Y family DNA polymerases, found throughout evolution, have the specialized ability to copy damaged DNA. The two Escherichia coli Y family DNA polymerases, UmuD'2C (pol V) and DinB (pol IV), bypass distinct types of DNA damage. Specifically, UmuD'2C bypasses abasic sites and thymine-thymine dimers, whereas DinB specializes in bypass of N2-dG adducts such as N2-furfuryl-dG. Using hydroxylamine mutagenesis, we generated a library of UmuC mutations from which we selected those that had the ability to confer survival to nitrofurazone, which is believed to cause predominantly N2-furfuryl-dG lesions. The six selected UmuC variants each confer resistance to nitrofurazone as well as to UV radiation, indicating that the mutations serve to broaden specificity for DNA damage. In addition, further characterization suggests that some of these variants disrupt interactions with the umuD gene products. Our findings suggest that lesion recognition may be a function of protein interactions as well as active site architecture.

Point mutations in <i>Escherichia coli</i> DNA pol V that confer resistance to non-cognate DNA damage

244th National Meeting (2012)

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Point mutations in Escherichia coli DNA pol V that confer resistance to non-cognate DNA damage