Figure 7

Root locus plots of recA to uvrA SISO system. Fig. 7a Root locus plot of ALDH2A1 to IDH2 system exposed to normal air with negative feedback is shown, with large stability margins. Fig. 7b Root locus plot of ALDH2A1 to IDH2 system exposed to poisonous air with negative feedback, where the locus on the positive real axis is entirely outside of the unit circle and therefore it has no stability margin. Fig. 7c Root locus plot of ALDH2A1 to IDH2 system exposed to poisonous air with positive feedback, showing no stability margin because of the locus at the right.