Figure 3
Divalent cation requirements for LigA activity. A. Titration of MgCl2, MnCl2 and CaCl2. Ligation assays were performed with 60 fmol of LigA wt and increasing amounts of divalent cations, and quantified as described in Methods. Ligation activity obtained with 1 mM MnCl2 was set as 100% and relative DNA ligation activity is shown as the average of 2 experiments. B. Titration of CoCl2, NiCl2 and ZnCl2. Ligation assays were performed as in A. Note that the ordinate has a scale of about 2 orders of magnitude lower than in A for better illustration of the divalent cation optima.