Figure 5.

The binding thermodynamics of Orai-CMBD to CaM and CaM( 1TnC ) determined by ITC. A solution of 30 μM CaM (A) or CaM(1TnC) (B) was titrated with 1 mM Orai-CMBD in 10 mM Tris, pH 7.5, 0.1 M NaCl, 2 mM Ca²⁺. The upper panels show the heat evolved per injection and the lower panels show the integrated heat per injection versus the molar ratio. The model for the fitting was “one set of sites” for CaM and two sequential binding sites for CaM(1TnC). In both cases, the middle points of the thermograms indicates a stoichiometry of 1:2 protein:ligand binding. The values from the fitting are shown in Table 4.