Fig. 7.

Mo-EPR of CO dehydrogenases (12 mg ml⁻¹; 50 mM HEPES, pH 7.2) from O. carboxidovorans wild type and the mutants E::km, F::km, or G::km (from top to bottom). The enzymes were exposed to CO (a) or treated with 5 mM sodium dithionite (b). Spectra were recorded at 120 K at a microwave frequency, modulation amplitude, and microwave power of 9.47 GHz, 1 mT and 10 mW, respectively