Three mutations in pGB-<i>ruvAz60</i> are necessary and sufficient to inactivate RFR.

aSurvival of ruvA100 mutant (JJC2971) containing different plasmids after 40 Joules/m2 UV irradiation. bPlating of dnaEts recF recB ruvA100 (JJC3110) containing different plasmids at 37°C. (+) 50 to 100% plating efficiency, (−) less than 0.01% plating efficiency, (+/−) or (+/−) 0.01 to 10% plating efficiency. cPercentage of DNA entering pulse field gels in dnaEts recF recB ruvA100 cells containing different plasmids (42°C). Results are the average of 2 or 3 independent experiments except pGB-ruvAz3 (H29R K129E F140S) which was tested 5 times, pF1m-F3m (H29R E40G K129E F140S) 7 times, and pF4m (S177G D184N) which was tested once. dThis triple mutant was called ruvAz3 and was used for further analysis. eThis mutant was fortuitously obtained during the construction of pF1m1–F3m1 by site directed mutagenesis.