Figure 9

Iron decreases APP IRE mRNA·IRP1 binding by changing kon and koff. APP mRNA·IRP1 complex was diluted in the stopped-flow cell with an equal volume of the titration buffer alone, curve (A) and 50 μM Fe2+ in the titration buffer, curve (B). Traces were best fit with the single-exponential function. The concentration of APP mRNA was 1 μM, and IRP1 was 0.1 μM after mixing. Data points were averaged from three independent experiments. The koff value was obtained from the Keq values and using Kd = koff/kon.