Many Bacteria Use a Special Mutagenic Pol III in Place of Pol V

Abstract

Synopsis All bacteria contain specialized polymerases that are required for bypassing unrepairable lesions and for mutagenesis. In the well-characterized E. coli system, these include the Pol Y family polymerases, Pol IV and Pol V. Yet, many bacteria lack Pol V and contain, in its place, a special mutagenic Pol III (ImuC) that appears to exert its action in concert with two additional proteins, often found in the same operon, ImuA and ImuB. ImuC differs from replicative DnaE by a series of conserved amino acid changes in the enzyme's active site.