Figure 2

Temperature affects the binding affinity of FRT IRE-RNA with IRP1 repressor protein in presence of metal ions (Mn²⁺). Panel A, Anisotropy values of FRT IRE-RNA at 10 °C (‒○‒) and 25 °C (‒⦁‒) with IRP1 protein plus Mn²⁺. Panel B, the anisotropy values of ACO2 IRE-RNA at 10 °C (‒∆‒) and 25 °C (‒▲‒) with IRP1 protein plus Mn²⁺. The fluorescein tag IRE-RNA concentration was 50 nM and Mn²⁺ was 50 µM in titration buffer. The excitation and emission wavelength were 490 and 520 nm, respectively. The curves were fit to obtain dissociation constant (K _d) as described in Experimental Procedure. The solid lines are the fitted curves.