Figure 7

Recombinogenic activity of RecA variants. (A) The scheme represents the recombination and reconstitution of lacZ gene after conjugation and consequent recombination between the fragments lacZΔT of the donor and lacZΔP of the recipient. (B) Recombination was assessed by measuring the β-galactosidase activity resulting from the restoration of an intact lacZ gene after conjugation of MG1655 nalR lacZΔP recA::Cm cells harbouring pQE-80L plasmid derivatives containing each of the seven recA variants with Hfr3000 lacZΔT CmR under protein induction with 0.05 mM IPTG. The β-galactosidase activity was assessed by Miller’s assay. The ratios of β-galactosidase activity in the presence of the variant versus β-galactosidase activity in the presence of EcRecA, used as a reference, were calculated for 3 different biological experiments. These ratios are plotted as a histogram. The strains analysed are RecA + strain (blue dot filled bar), ΔrecA strain (unfilled bar), the ∆recA strain producing EcRecA (blue filled bar, it is the reference but is presented for visual comprehension) and ∆recA strains producing PaRecA, DrRecA, EcPa, EcRecAV1 and EcRecAV2 variants (blue dot filled bars). NS indicates a non-significant p-value (from the one sample t test compared to 1, the EcRecA value), * indicates a significant p-value < 0.05 and ** a significant p-value < 0.005. Error-bars indicates SD.