Fig. 3.

Characterization of CrHydA1 maturated with syn-B. (A) X-band CW EPR spectra of [syn-B]-CrHydA1 (Left) and [syn-B-¹³CN]-CrHydA1 (Right). Both spectra were simulated with 2 components: H_ox, shown in red traces, and H_ox-CO, in gray traces. Conditions were as follows: temperature, 30 K; microwave power, 0.05 mW. (B) H₂ evolution activity of [syn-B]-CrHydA1 and a holo-CrHydA1 standard measured at 20 °C. (C) Q-band Davies ENDOR spectrum of [syn-B-¹³CN]-CrHydA1 H_ox and [2-¹³C-Tyr]-CrHydA1 H_ox recorded at g = 2.102 (g₁ of H_ox). Conditions were as follows: frequency = 34.1 GHz; temperature = 15 K; inversion pulse = 80 ns; τ = 300 ns; radiofrequency pulse = 20 µs.