Fig. 4
From: Dynamic allocation of orthogonal ribosomes facilitates uncoupling of co-expressed genes
Resource allocation control increases production of violacein. Violacein is produce from l-tryptophan by a five-enzyme pathway. Experimentally the pathway is divided into two cassettes. vioA is constitutive expressed. The vioBCDE cassette is inducible under the control of AHL. Ribosomes are directed between the cassettes by use of ribosome binding sites as described previously. Simulations show the steady-state concentrations of the pathway enzymes and final metabolite. Note that the enzymes are divided by induction mechanism so that the downstream enzymes are depicted in the same colour. Variation in their levels is determined by protein size only. Scaled metabolite production represents the steady-state amount of the final metabolite in the pathway, scaled by the highest amount achieved across the induction. ω A = 25 molecules per min. ω ρ = 500 molecules per min. The downstream cassette is induced as shown by varying ω BCDE . These enzymes are translated by the host ribosome pool throughout. Other parameters are detailed in Supplementary Note 9. a Single resource pool. Use of host ribosomes by all genes. b Simple resource allocation scheme. vioA translation by the orthogonal ribosome system. c Simulation of the cassettes sharing a single pool of resources. Enzyme A is expressed utilising the host system. d Simple resource allocation scheme by allocating enzyme A to the orthogonal ribosome pool. e Violacein production in vivo per cell at 24 h post induction. Normalised by the largest production per cell achieved across all conditions. Bars represent means ± 1 SD. N = 3
