Spectroscopy characterization of PhDph2 mutants. a. UV-Vis spectroscopy of as purified PhDph2 wild type (black line), single mutants: C59A (red line), C163A (blue line), C287A (green line) and double mutant(pink line); b. UV-Vis spectroscopy of single mutant PhDph2 C59A with and without dithionite; c. EPR spectra of wild type PhDph2 and its single mutants in the reduced [4Fe – 4S]1+ state at 12 K. The principal values of g-factor for the main spectral component (shown for wild type and C163A with arrows of corresponding color) are: WT: 2.03, 1.92, 1.86; C287A: 2.01, 1.94, 1.88. S59A: 2.03, 1.94, 1.90; C163A: 2.11, 1.91, 1.793;