FIG. 7.
DNA unwinding activity of PcrASpn. DNA relaxation assays were performed as described in Materials and Methods. Plasmid pT181cop608 DNA was incubated in the presence (+) or absence (−) of RepC and/or different amounts of either His-tagged PcrASau or PcrASpn. The products were separated by 1% agarose gel electrophoresis in the presence of ethidium bromide. OC, nicked open circular DNA; D, supercoiled dimeric plasmid DNA; RelD, covalently closed relaxed dimeric DNA; SC, supercoiled monomeric plasmid DNA; Rel, covalently closed relaxed monomeric DNA; form U, unwound plasmid DNA.