Figure 3.

Purified ParM and ParR stimulate TraI relaxase activity. An oriT-carrying plasmid substrate was preincubated with increasing concentrations of ParM or ParR before addition of 25 nM TraI. The yield of open circular DNA relative to supercoiled substrate after 20 min reaction was visualized by agarose gel electrophoresis and band intensity measured with ImageJ. Stimulation of TraI relaxase activity by ParM alone (A) or ParR alone (B) is shown with representative curves. (C) Stimulation of TraI (25 nM) was measured with ParM (15 nM) or ParR (15 nM) alone and in combination. BSA (500 nM) served as negative control. Standard deviations are shown, n = 3, significance was determined using a one-sided t-test, ***P < 0.001.