Figure 1. Transcriptional coordination of catabolism and anabolism.

1. Schematic of metabolism—separated into catabolism (blue), central metabolic precursors (e.g., alpha‐keto acids, black), and anabolism (red)—and the cyclic AMP (cAMP)‐dependent Crp regulatory circuit in Escherichia coli. By titrating the expression of carbon uptake proteins, catabolic limitation can be imposed externally. Conversely, by titrating the expression of the enzyme glutamate synthase (GOGAT), a limitation of anabolic capacity can be imposed externally. N: nitrogen. GS: glutamine synthase. See Appendix Fig S1 and Appendix Text 1 for detailed description of titration strains.
2. Steady‐state expression of Crp‐activated (left panel) or constitutive (right panel) fluorescent transcriptional reporters at varying external cyclic AMP concentrations (white and black colors denote lowest and highest external cyclic AMP concentration, respectively) in a strain that cannot produce or degrade endogenous cAMP (NQ1399, ΔcyaAΔcpdA). Small gray circles: individual biological replicates (n = 2–4). Large circles: mean across replicates.
3. Catabolic and anabolic fraction of E. coli’s proteome in catabolic (blue) and anabolic (red) limitation (data from Ref. Hui et al, 2015 with few excluded proteins, see Appendix Text 3), as well as at varying external cAMP concentrations in strain NQ1399.