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. Author manuscript; available in PMC: 2008 Dec 11.
Published in final edited form as: J Mol Biol. 2008 Mar 19;378(4):761–777. doi: 10.1016/j.jmb.2008.03.023

Figure 2.

Figure 2

Effects of Mg2+ on the [Na+]-dependence of the equilibrium constant (KBC,R) for RecBC binding to an end of reference DNA I. Values of log KBC,R for reference DNA I are plotted as a function of log [Na+]. The data were obtained from “salt-back titrations” as described in Materials and Methods in buffer M at 25°C in the presence of 10 mM MgCl2 (●) or in the absence of MgCl2 (○). Data were also obtained from direct measurement of KBC,R in buffer M plus the indicated [NaCl] in the presence of 10 mM MgCl2 (▲) or in the absence of MgCl2 (△). The solid and short dash lines are linear fits to the data obtained in buffer M with or without 10 mM MgCl2, respectively. The slopes obtained from the linear fits are −1.9 ± 0.4 in the presence of 10 mM MgCl2 and −4.5 ± 0.6 in the absence of MgCl2.