Figure 3.

DMs inhibit the restriction activity of EcoR124I. Reaction mixtures containing increasing concentrations of DM1, DM1–SS–DM1, DM2–SS–DM2 (A ) and control peptides DM_scr–SS–DM_scr and DM_c–SS–DM_c and Ocr99 (B) from ATPase assays were analyzed by agarose gel electrophoresis to monitor DNA cleavage. All reactions were initiated by addition of scDNA. [scDNA] = 5 nM, [EcoR124I] = 5 nM. The sizes of the DNA molecular weight marker (M) are in kilobase-pairs. C) The % of scDNA remaining in the presence of 50 μM peptide (except DM1–SS–DM1 at 40 μM and Ocr99 at 0.5 μM) was determined by densitometric analysis of agarose gels (n≥ 4 independent experiments). *scDNA digested in the absence of peptide inhibitor. **scDNA alone. N, nicked circular DNA; l, linear and sc, negatively supercoiled