FIGURE 3.

EPR spectra of the affinity-purified NarE. EPR spectrum of 0.1 mm NarE in 50 mm potassium phosphate buffer, pH 7.4, 250 mm imidazole, and 300 mm NaCl (a). NarE spectra were also recorded in the same buffer in the presence of 10 mm FeCl₃ (b) and 5 mm K₃Fe(CN)₆ (c). Similar results were observed for three independent experiments. mT, millitesla.