(A) Steady-state cleavage profile of endogenous MgtE processed by endogenous and ectopically overexpressed YqgP from the inducible Phyperspank promoter in living B. subtilis (BTM2 and BTM501, respectively, Table EV2), in minimal medium at low magnesium concentration (10 µM). Strain lacking YqgP (ΔyqgP, BTM78, Table EV2) was used as a control. Proteins were detected by immunoblotting with chemiluminescence detection. Data information: In all panels, endogenous full-length MgtE is indicated by a black arrow, and N-terminal cleavage product by red arrows. Endogenous MgtE was visualised by anti-MgtE(2-275) (α-MgtE) 