(C) Similar analysis of the same strains but grown in minimal M9 medium (with 10 µM MgSO4) supplemented with increasing concentrations of MnCl­­2. Black arrows denote full-length substrate (MgtE), red arrows denote the cleavage products generated by YqgP. (D) Western blots of four independent experiments shown in panel (C) were quantified by near-infrared fluorescence detection, quantified by densitometry and the results are displayed as fold activation of MgtE cleavage at 100 µM MnCl­­2 relative to 1 µM MnCl­­2 activity. Average values and all fours datapoints are plotted for each indicated YqgP variant. 