Figure 1: Thermodynamic stability of the CyaY/IscS and IscU/IscS complexes.

(a) Binding isotherm for the interaction of IscU with IscS. In the upper panel, peaks indicate the heat released after each addition of IscU into the protein solution. In the lower panel, the data were best fit using a single binding constant to calculate the thermodynamic parameters (continuous line). (b) Binding isotherm for the interaction of CyaY with IscS. In the upper panel, peaks indicate the heat released after each addition of CyaY into the protein solution. In the lower panel, the data were fit using a single binding constant.