FIGURE 4.

Analysis of the effect of calcium on RapA2 thermal stability. A, far-UV CD spectra of RapA2 were recorded at temperatures ranging from 0 to 95 °C. The ellipticity at 209 nm of RapA2 in the absence (apo-form, line) or in the presence of 0.5 mm CaCl₂ (holo-form, dashed line) is depicted at different temperatures. B, the reversibility of thermal-induced denaturation of the apo- and holo-forms of RapA2 was determined. Far-UV CD spectra were recorded at 15 °C and 95 °C, and after cooling to 15 °C the samples submitted to 95 °C.