Fig. 2
From: Uncoupling conformational states from activity in an allosteric enzyme
CoSPI discovery of a non-essential activator of ATP-PRT. a l-His IC 50 and %Activity data obtained in the presence of each of 11 l-His analogues using CoSPI. The dashed lines mark l-His IC 50 and the activity of uninhibited ATP-PRT. Error bars indicate the s.d. Number of replicates (n) = 3 b Representative inhibition curves determined for l-His in the presence of 0 (black), 0.5 (purple), 1 (orange), 2 (yellow) and 4 (green) mM compound 2, TIH (shown in the upper right corner). Circles are experimental measurements and lines the best fit to Eq. 2 in Methods section. c Replot of the data in b, showing hyperbolic increase in ATP-PRT activity (circles) and linear increase in l-His IC 50 (squares), in the presence of TIH. The lines are the best fit to Eq. 1 in Methods and a linear regression of the data, respectively. Error bars indicate the s.e.m. d Steady-state kinetics of ATP-PRT activation by TIH. Circles are data points and the line is the best fit to Eq. 3 in Methods section, n = 2. e General modifier mechanism depicting an activator, E, enzyme; S, substrate; A, activator; P, product. f Double-reciprocal plot highlighting the non-essential activation pattern obtained when varying the concentration of TIH. Circles are data points obtained with 0 (black), 0.25 (red), 0.8 (blue) and 4 (green) mM TIH and lines are the best fit of the entire data set to Eq. 4 in Methods section. Error bars indicate the s.d., n = 2
