FIGURE 3.

Tyr¹⁴⁹⁴ and Tyr¹⁴⁹⁵ are CaM C-lobe binding determinants. A–F, representative ITC traces for titration of C-terminal calmodulin lobe into DIII-IV linker peptides with thermodynamic properties and binding parameters shown in Table 2. The data show that the Ala substitutions are well tolerated, save Y1494A and Y1495A, which show significant endothermic binding. This endothermic binding suggests that the low heat signals obtained for full-length CaM to the same mutants, especially Y1494A, in Fig. 2 result from enthalpy/entropy compensation (see “Results” for details).