Figure 1.

Characterization of HO2 in the Fe³⁺-heme-bound forms. (A) Absorbance spectra of 5 μM Fe³⁺-HO2_core (…), Fe³⁺-HO2_tail^R (---), or Fe³⁺-HO2_sol^R (—) in 50 mM Tris (pH 8.0) and 50 mM KCl at 20 °C. (B) EPR spectra of Fe³⁺-HO2_core, Fe³⁺-HO2_tail^R, Fe³⁺-HO2_sol^R, and Fe³⁺-HO2_sol(H45A)^R. Samples were prepared and run as described (see Methods). The g values are indicated above the spectra.