HYSCORE spectra of IspH•CN. A, Experimental HYSCORE spectrum of EcIspH•13C15N. Sample is reduced ([Fe4S4]+) with dithionite. B, Simulation of 13C hyperfine coupling with A = [−3.9, −3.8, 0.1] MHz, Euler angle = [0, 40±5, 0]°. C, Simulation of 15N hyperfine coupling with A = [1.1, 1.1, 2.3] MHz, Euler angle = [0, 30±10, 0]°. Euler angle follows zyz convention.