Figure 4. Roles of Sfh5 residues Y175 and H173 in heme binding and Fe-center chemistry.
(A) The color intensities of solutions (30 μM) of purified recombinant Sfh5 (left), Sfh5H173A (middle) and Sfh5Y175F (right) are compared. (B) UV-vis absorption spectra of Sfh5, Sfh5H173A, Sfh5Y175A and Sfh5Y175F are shown. The protein concentrations were fixed at 30 μM. (C, D) UV-vis spectra of Sfh5H173Y and Sfh5Y175H are shown, respectively. Spectra obtained after reduction of sample with dithionite are in red. Sfh5H173Y did not undergo a spectral shift upon reduction.