Role of Charged Residues in the Catalytic Sites of Escherichia coli ATP Synthase
Figure 5
Loss of Pi protection from inactivation by NBD-Cl inhibition with inserted negative charge. Membranes were preincubated with Pi at zero, 2.5 or 10 mM concentration as shown, for 60 min at 23°C. Then, NBD-Cl (125 μM) was added and aliquots withdrawn for assay at time intervals as shown. ATPase activity remaining is plotted against time of incubation with NBD-Cl. ○, no Pi added; □, 2.5 mM Pi; Δ, 10 mM Pi. Data taken from [82, 86].