The absorbance spectra of WT LodA and LodA variants. A. The absorbance spectrum of WT LodA with the visible absorbance features of CTQ magnified in the inset. B. The visible absorbance spectra of LodA variants in this study. The 280 nm absorbance in each of these spectra is identical so the observed variations in the intensity of the absorbance reflect the variation in A400/A280 nm of these variant proteins. The spectra from top to bottom are C448D, Y211A, Y211E, WT, C448A, Y211F, K530A and K530R LodA.