Characterization of DosT using EPR and UV-visible spectroscopy. (A) UV-visible spectroscopy characterization of DosT (3 μM in 20 mM Tris, pH 7.5) as purified, exposed to DTH, followed by air exposure. (Inset) An enlarged image of the 500- to 600-nm region. (B) EPR spectroscopy analysis of purified DosT (6 μM) after treatment with Fe(CN)63−. No EPR signal was detected with purified DosT without Fe(CN)63− exposure. (C) UV-visible spectrum of DosT exposed to air followed by DTH treatment, the former treated with KCN, and exposed to Fe(CN)63− followed by KCN. Numbers in parentheses indicate absorption maximum in nanometers.