Figure 5.
Electronic absorption (A) and MCD (B) spectra of Fe(II)E75(LBD). A) The electronic absorption spectrum at 25 °C of Fe(II)E75(LBD) (black line) after the addition of solid sodium dithionite to Fe(III)E75(LBD) (thin gray line) is shown. The sample contained ~8 µM heme in 25 mM EPPS with 100 mM NaCl, pH 8.0. B) The MCD sample was ~20 µM heme in 25 mM EPPS with 250 mM NaCl, pH 8.0, ~55% glycerol. Reduction was performed using solid sodium dithionite. The averages of three scans at 4.5, 8, 15 and 25 K at constant magnetic field (7 tesla) are shown.