Figure 5
From: A functional type I topoisomerase from Pseudomonas aeruginosa
MgCl 2 is required for DNA relaxation. Lane 1 shows relaxed DNA (R) containing 110 ng pUC18 DNA and 9 ng PAT in topoisomerase buffer with 2.5 mM MgCl2 and lane 2 shows supercoiled (S) DNA without PAT. Reaction mixtures containing 110 ng of supercoiled pUC18, 9 ng of PAT and increasing concentration of MgCl2, 0, 0.00025, 0.0025, 0.025, 0.25, 2.5 mM in lanes 3–8, respectively.