Fig 3.

Effects of ADP, ATP, and 2-oxoglutarate on the activity of the DraT-GlnB complex. DraT activity was assessed indirectly from Fe protein activity by measuring hydrogen evolution. Reaction mixtures for the DraT assay contained 4 mM MgCl₂, copurified DraT-GlnB complex, 100 μg A. vinelandii Fe protein, and the effectors, as indicated. For a control, the reaction was performed in the presence of copurified DraT-GlnB complex in the absence of NAD⁺. The DraT activity was stopped by reducing NAD⁺ using dithionite solution. The Fe protein activity was determined by adding 500 μg of MoFe protein, and the hydrogen production was measured. ns, nonsignificant; *, P < 0.05. The error bars represent the calculated standard deviations.