Modelling the regulatory co-activation behaviour of PEPC upon FBP and Acetyl-CoA binding.

(A) Comparison of the kinetic behaviour described by the empirical model of Lee et al. [59] (blue line) and the best sampled kinetics using our framework (red line) with and without Acetyl-CoA. The substrates concentrations used in each case were: 2 mM PEP, 10 mM bicarbonate, 15 mM FBP and 0.63 mM acetyl-CoA, which correspond to the physiological concentrations found in E. coli in glucose-limited cultures [58]. The red shaded area denotes a 99% confidence region for 10⁴ instances sampled. (B) Comparison of the kinetic behaviours including additional information during the sampling. The legends and concentrations used are the same as in (A). (C) Hill coefficient curves for the most accurate PEPC model sampled in the presence and absence of FBP and acetyl-CoA at physiological concentrations. The coloured circles denote experimentally determined Hill coefficients under conditions resembling physiological concentrations of PEP, FBP and acetyl-CoA [55]. (D) Regulatory kinetic behaviour described by the PEPC model with 15 mM of FBP (black circles), i.e. physiological condition, and 0.45 mM of FBP (black squares), i.e. carbon-starvation condition, for different acetyl-CoA concentrations. The dashed line represents the physiological concentration of 0.63 mM Acetyl-CoA found in E. coli under normal physiological conditions.