Fig 6. Tb³⁺-induced fluorescence emission spectra of the different CaM species.

(A) The fluorescence emission spectra (520–580 nm) of wild type (wt) CaM and the indicated CaM mutants (10 μM) was recorded in a buffer containing 10 mM Pipes-HCl (pH 6.5) and 100 mM KCl in the absence and presence of increasing concentrations of TbCl₃ (10–200 μM) as described in Materials and Methods. (B, C) The plots present the emission fluorescence at 543 nm of wild type (wt) CaM and the indicated CaM mutants (10 μM) at increasing concentrations of TbCl₃ in the conditions described in A.