The CuA redox-dependent binding of cyanide and azide to the Mn center of R.s. oxidase. Spectra taken at 9.46 GHz, 50 μW power, 100 kHz modulation frequency, 13 G modulation amplitude, and 327 ms conversion time. Conditions: 90 μM R.s. oxidase, 100 mM K+-HEPES, and 4 mM KCl, pH 7.0; cyanide/azide, 5 mM; dithionite, 10 mM.