Figure 9.

Use of CaM mutants to monitor the interaction between CaM and Cx peptides. (A and B) Interaction of the Cx peptides with 5 μM CaM mutants T26W and Y99W. Fluorescence emission was acquired from 325 nm to 415 nm with excitation wavelength at 295 in the absence (solid line) or presence of Cx44_129–150 (▴) and Cx43_136–158 (♦). The inset showed the normalized signal changes (integrated area from 325 nm to 415 nm) as a function of added Cx peptides in 50 mM Tris, 5 mM Ca Cl₂, 100 mM KCl at pH 7.5. (C and D) Acrylamide quenching of the tryptophan fluorescence in CaM mutants T26W and Y99W in the absence (○) or presence of Cx44_129–150 (▴) or Cx43_136–158 (♦).