Question

Why is the observed mutation rate of E. coli ${\mathbf{10}}^{\mathbf{-}\mathbf{8}}$to ${\mathbf{10}}^{\mathbf{-}\mathbf{10}}$per base pair replicated, even though the error rates of PolI and Pol IIare${\mathbf{10}}^{\mathbf{-}\mathbf{6}}$to${\mathbf{10}}^{\mathbf{-}\mathbf{7}}$per base pair replicated?

Short answer

The observed mutation rate of E. coli is ${10}^{-8}$to ${10}^{-10}$per base pair replicated, even though the error rates of Pol I and Pol II are ${10}^{-6}$to ${10}^{-7}$per base pair replicated as mismatch repair and other DNA repair mechanisms help to proofread the base pairs that polymerases miss.

Step-by-step solution

Explanation of Concept

DNA damage may occur under stressful conditions (e.g., toxic clones harbored in the cell), activating the SOS response and inducing approximately 40 members of the SOS regulon.

DNA Repair Mechanisms

The mismatch repair and other DNA repair processes help to proofread the base pairs that polymerases miss. So, the reported mutation rate of E. coli is ${10}^{-8}$to ${10}^{-10}$ per base pair repeated, despite the mistake rates of Pol I and Pol II being ${10}^{-6}$ to${10}^{-7}$ per base pair replicated.