Nuclease activity of NurA on different DNA substrates.

<p>NurA nuclease activity on linear single-stranded DNA labeled at its 3’-end (A) or 5’-end (B). A time course analysis has been conducted to analyze NurA nuclease activity on these substrates in order to visualize the whole different products coming out from its activity. (C) NurA endonuclease activity on a single-stranded DNA (M13). Increasing concentrations of NurA (from 0.6 to 12.5 pmoles) have been used to test its endonuclease activity on a circular single-stranded DNA (lanes 2–6). Lane 1 is a control in which M13 has been incubated with no protein. (D) Analysis of NurA endonuclease activity on a circular double-stranded DNA. Increasing amounts of NurA (from 0.1 to 7.5 pmoles) have been analyzed for its endonuclease activity (lanes 2–7). A control lane with no protein has been run (lane 1). Control experiments were conducted to compare the activity of NurA (lane 9) and 0,1 nmol of commercial DNaseI (lane 10). A control lane with no protein has been run (lane 7). (E) Increasing amounts (1, 2.5, 5 and 10 pmoles) of NurA D58A were analyzed for their nuclease activity (lanes 2–5), on circular double-stranded DNA, lane 1 refers to control in which the only substrate has been loaded, lanes 6 and 7 refer to NurA wt alone as positive control (5 and 10 pmoles).