FIGURE 3.
X band EPR spectra of the WT enzyme at 10 K. A, spectrum of ferricyanide-oxidized enzyme (bottom) and a sample poised at +520 mV in the presence of redox mediators (middle) both in 100 mm MES, pH 6.0, 100 mm K2SO4, and 0.05% DDM are shown. The top spectrum is obtained at a redox potential of ∼+100 mV. The g values of the main signals are marked. B, changes of a signal intensity at g = 5.20 (•) upon a redox titration are shown. The experimental data are fitted by two theoretical Nernstian n = 1 curves with the Em values -60 and 351 mV.