A) Far UV circular dichroism spectra of CaHydA WT (full line) and C298D (dashed line).

<p>Spectra were acquired under aerobic conditions in 50 mM Tris·HCl, 200 mM KCl, pH 8.0. C298D mutation does not cause significant differences in secondary structure. <b>B</b>) <b>UV-visible absorbance spectra of oxidised CaHydA WT (full line) and C298D (dashed line).</b> Spectra were acquired under aerobic conditions in 50 mM Tris·HCl, 200 mM KCl, pH 8.0. <b>C</b>) <b>Visible circular dichroism spectra of oxidised CaHydA WT (full line) and C298D (dashed line).</b> A different behaviour is observed between 250–300 nm, whereas the visible region does not show any difference, demonstrating identical insertion of iron sulphur clusters.