Figure 2.

Recombination-product distributions of four natively supercoiled Int recombination substrates (σ_avg = −0.055 ± 0.005). (A) Control plasmids. (B) A-tract-containing plasmids. Each recombination reaction was incubated for 30 min at the indicated temperature and analyzed by agarose gel electrophoresis. The number of irreducible knot crossings, Kn, corresponding to each band are shown. Other species are labeled as follows: oc, open-circular (unknotted); lin, linear; sc, supercoiled substrate. Each histogram represents the average of at least three experiments; error bars indicate one standard deviation.