Fig. 2.
Response of NifA to oxidized Nhis6NifL and Nhis6NifL-R306C. NifA activity was measured by the formation of open-promoter complexes, as described in Methods, and plotted relative to the extent of NifA activity in the absence of NifL. Each data point is the mean of at least two independent experiments. All assays contained 4 mM GTP as hydrolyzable nucleotide and 250 nM NifA (calculated as a dimer). (A) Response of NifA to the indicated concentration of Nhis6NifL (calculated as a tetramer) in the absence (▪) or presence (□) of 0.05 mM ADP. (B) Response of NifA to the indicated concentration of Nhis6NifL-R306C (calculated as a tetramer) in the absence (▪) or presence (□) of 0.05 mM ADP.