FIG. 5.

In vitro gyrase cleavage. pBR322 Δ(EcoRI-BamHI) plasmids without (lanes 2 and 3) or with cloned fragments carrying the Mu SGS (lanes 4 and 5), the pSC101 gyrase site (lanes 6 and 7), or the nrdAB BIME (lanes 8 and 9) were linearized with PvuII restriction digestion and then incubated with DNA gyrase in the presence of enoxacin. Following treatment with SDS and proteinase K, the DNA fragments were separated on a 1% agarose gel and stained with ethidium bromide. The expected fragment sizes for cleavage at the gyrase site in question were as follows: pBR322, 2.8 + 1.2 kb; Mu, 2.9 + 2.6 kb; pSC101, 2.5 + 1.9 kb; nrd BIME, 2.4 + 1.8 kb. Lanes 1 and 10, molecular size markers. −, no gyrase; +, with gyrase.