Fig. 1.

Effects of temperature on K _D (A), and R _min and R _max (B) of furaptra measured in vitro in a 1-cm quartz cell at solution temperatures between 15 and 35°C. The solutions contained 0–150 mM KCl, 0–50 mM MgCl₂, 0.1 mM EGTA, 0.5 µM furaptra, and 10 mM MOPS, and the pH of the solution was adjusted by addition of KOH for each temperature. From a set of R values obtained at 0, 0.5, 1, 2, 5, 10, 20, and 50 mM Mg²⁺ concentrations, estimates of K _D (circles), R _min (triangles), and R _max (crosses) were obtained by use of the nonlinear least-squares fitting technique with Eq. 1. For each data set, the solid line was drawn by nonlinear least-squares fitting with a function of the form indicated in the graph (solid lines)