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. 2014 Jul 17;42(14):9005–9020. doi: 10.1093/nar/gku640

Figure 7.

Figure 7.

DNA-binding assays of Flag-tagged topo IIβ domain-deletion mutants in the absence of ATP. (A) Competitive binding of supercoiled (form I) and linear (form III) DNA to the enzyme (80 fmol) immobilized on beads. After incubating equimolar mixture (5 ng each) of supercoiled and linear DNA with the beads, bound and unbound DNA was fractionated by magnetic separation. DNA amounts in agarose gel bands were quantified by densitometry and plotted in the graph as percentages of input DNA (n = 3). (B) Effects of RNA on DNA binding. Five nanograms of supercoiled and linear DNAs were incubated separately with the enzyme (80 fmol). RNA was added as in Figure 6C. (C) Relative amounts of bound DNA as determined by densitometry of the gel images shown in (B). Supercoiled or linear DNA amounts bound to WT enzyme in the absence of RNA were set to 100%. Data points are mean with SD bar (n = 5). Asterisks indicate a significant deviation from ΔCTD (P < 0.005).