HerA modulates NurA nuclease activity on linear single-stranded DNA.

<p>NurA/HerA complex was analyzed for its nuclease activity on single-stranded DNA in the absence or in the presence of 5 mM ATP with ODN1 (A) or ODN2 (B) substrates. The proteins were incubated either separately in the absence of ATP (A and B, lanes 2 and 3) or mixed together using increasing amounts of HerA (from 3 to 18 pmoles) and 18 pmoles of NurA (A and B, lanes 4–7). In the presence of ATP, 7.5 pmoles of NurA and increasing amounts of HerA (from 5 to 12 pmoles) were analyzed either separately (A and B lanes 9–12) or mixed (A and B, lanes 13–15). The main products are indicated by curly braces for ODN1 and arrows for ODN2. Lane 1 refers to a control lane in which no protein has been added. (C) NurA/HerA complex nuclease activity on double stranded DNA. ODN1 has been previously annealed with its complementary strand in order to obtain a linear double-stranded DNA molecule (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0142345#sec002" target="_blank">Material and Methods</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0142345#pone.0142345.t001" target="_blank">Table 1</a>) 19 pmoles of NurA and 12 pmoles of HerA were analyzed separately without or with 5 mM ATP (lanes 2–3 and 7–8, respectively). Then the same amount of NurA was analyzed in the presence of increasing amounts of HerA (from 3 to 12 pmoles) in the absence or in the presence of ATP (lanes 4–6 and 9–11, respectively). Lane 1 refers to a control in which no protein was added in the assay. Lanes 12 refers to a 21 mer Cy5 used as marker.