Escherichia coli UmuC active site mutants: effects on translesion DNA synthesis, mutagenesis and cell survival.

ABSTRACT: Escherichia coli polymerase V (pol V/UmuD(2)'C) is a low-fidelity DNA polymerase that has recently been shown to avidly incorporate ribonucleotides (rNTPs) into undamaged DNA. The fidelity and sugar selectivity of pol V can be modified by missense mutations around the "steric gate" of UmuC. Here, we analyze the ability of three steric gate mutants of UmuC to facilitate translesion DNA synthesis (TLS) of a cyclobutane pyrimidine dimer (CPD) in vitro, and to promote UV-induced mutagenesis and cell survival in vivo. The pol V (UmuC_F10L) mutant discriminates against rNTP and incorrect dNTP incorporation much better than wild-type pol V and although exhibiting a reduced ability to bypass a CPD in vitro, does so with high-fidelity and consequently produces minimal UV-induced mutagenesis in vivo

SUBMITTER: Kuban W 

PROVIDER: S-EPMC3419331 | biostudies-literature | 2012 Sep

REPOSITORIES: biostudies-literature