FIGURE 5.

Affinities (K_D) of cMyBP-C motif and peptides binding to Ca²⁺/CaM determined from tryptophan fluorescence experiments. For each titration data set, the data points and fitted curves were obtained using the same approaches described in Fig. 3. For clarity of representation, each titration data set has been scaled by multiplying the following constants in the (F/F₀) values: motif, 0.9 (●); motif in 50 mm NaCl, 0.7 (■); Cpep, 0.2 (▴); and Npep, 0.1 (×). Each data point is the average of eight replicate measurements after correcting for solvent; the error bars (not shown; corresponding to ± 1 S.D.) are smaller than the symbols. All titrations were performed in the standard buffer except for “motif in 50 mm NaCl” data, which used a reduced NaCl concentration (see details under “Experimental Procedures”).