Figure 4.
Resistance due to the TrpE H170R mutation results from loss of allosteric feedback inhibition
(A) Inhibition of TrpE by C1 and 4-AI was studied in the presence of saturating concentrations of chorismate (50 μM) and NH4+ (100 mM). Inhibition is reported as percent activity relative to the no inhibitor control.
(B) Steady-state kinetics of WT TrpE and the H170R variant were studied under varying chorismate concentrations by directly monitoring formation of the fluorescent product, anthanilate.
(C) Allosteric feedback inhibition of TrpE WT and the H170R mutant was measured under increasing concentrations of L-Trp and presented as percent activity relative to the no L-Trp control. Data in all panels represent mean ± SEM (n = 3).