Figure 2

Spectral characteristics of Case12 (a,c,e,g) and Case16 (b,d,f,h). a,b. Maximum fluorescent responses. Fluorescent spectra recorded in the presence of 0.5 mM EGTA (dashed lines) or 1 mM Ca²⁺ (solid lines) at pH 7.4. c,d. Absorbance in the presence of 0.5 mM EGTA (dashed lines) or 0.4 mM Ca²⁺ (solid lines) at pH 7.4. e,f. Dependence of sensors fluorescence on pH in the presence of 0.5 mM EGTA (dashed lines) or of 0.2 mM Ca²⁺ (solid lines). g,h. Ca²⁺ titration curves, at pH 7.4.