FIGURE 6.
Circular dichroism spectra of wild type and HCM cTnC mutations. Far-UV CD spectra were performed in apo, Mg2+-bound, and Ca2+/Mg2+-bound states. Spectra were recorded at 195–250 nm utilizing a 1-mm-path quartz cell in a Jasco-720 spectropolarimeter at room temperature (20 °C). The spectra shown are the average of three independent measurements. For each independent measurement 10 scans were averaged, and no numerical smoothing was applied. The optical activity of the buffer was subtracted from relevant protein spectra. The buffer conditions were as described under “Experimental Procedures.” Mean residue ellipticity ([θ]MRE in degree·cm2/dmol) for the spectra was calculated utilizing the same Jasco system software and the following equation: [θ]MRE = [θ]/(10 × Cr × l) where [θ] is the measured ellipticity in millidegrees, Cr is the mean residue molar concentration, and l is the path length in cm. deg, degrees.