Bistability in a Metabolic Network Underpins the De Novo Evolution of Colony Switching in Pseudomonas fluorescens
Fig 2
Intracellular metabolic pathways downstream of carB.
The pyrimidine biosynthetic pathway is a molecular link between the mutant carB genotype and the CAP capsule phenotype. The switch-causing carB mutation reduces concentrations of intermediates in the pyrimidine biosynthesis pathway (shown in black), exposing a decision point at which uridine triphosphate (UTP) is used either by PyrG for nucleotide biosynthesis (leading to the Cap- phenotype, components in red), or by GalU for polymer biosynthesis (generating Cap+ phenotype, components in blue). Metabolic pathways related to UTP biosynthesis are shown in grey. High-flux reactions recycling nucleotides are shown by thick arrows, and nucleotide biosynthetic pathways are shown by thin arrows. Figure based on amino acid homology with established Escherichia coli pathways [14].