Figure 3. Respective abilities of mutant β clamp proteins to support DNA damage-induced mutagenesis.

Frequencies of (A) UV- or (B) MMS-induced mutagenesis were measured as described in Material and Methods using strains RW118 (WT; dnaN⁺ umuD⁺C⁺), RW120 (ΔumuD; dnaN⁺ ΔumuDC595::cat), or the umuD⁺C⁺ plasmid shuffle strains MS202 (β⁺), MS203 (β^Q61K), MS204 (β^S107L), MS205 (β^G157S), MS206 (β^V170M), MS207 (β^E202K) and MS208 (β^M204K), as indicated. Results represent the average of 5 independent determinations. Error bars represent one standard deviation. P-values ≤0.05 are indicated, and were calculated using the Student's t-test.