Fig. 6.

In vitro interaction of dansyl-CaM, -CML13, or -CML14 with IQ domain synthetic peptides of ATM1-IQ1 and ATM2-IQ1. Dansyl fluorescence was measured over an emission wavelength (λ) window from 400 nm to 600 nm or 650 nm and an excitation wavelength of 360 nm. Samples of 3 µM dansyl-CML13, dansyl-CML14, or using 600 nM dansyl-CaM, were separately tested for fluorescence alone, or in the presence (A, C, E, respectively) of ATM1-IQ1 or (B, D, E, respectively) ATM2-IQ1 peptide under conditions of Ca²⁺ (left panels) or EGTA (right panels). Peptide concentrations were used at a 10-fold molar excess. Spectra were collected for dansyl-CaM and dansyl-CMLs in the presence or absence of IQ peptides as indicated. The intensity was measured in arbitrary relative fluorescence units (RFU). The fluorescence traces are the mean ±SD of three independent experiments performed in triplicate.