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Mechanistic model of nutrient uptake explains dichotomy between marine oligotrophic and copiotrophic bacteria
Fig 5
A rate–affinity trade-off.
Plots show the results of proteome allocation problems using either PTS or ABC transport and solved for different extracellular nutrient concentrations (x-axis). We assume that the transport association rate is 100 times lower for ABC transport than for PTS (k′1 = 0.01k1) but that the translocation rate as well as the transport unit dissociation constant are equal (
). We additionally limit the radius of the cell to a minimum of 60 nm, corresponding to a maximum surface-area-to-volume ratio of 50 μm-1. (A) shows the maximal growth rates achieved using the optimal proteome allocation, and (B) shows the optimal surface-area-to-volume ratio used to achieve those maximal growth rates. ABC transport achieves higher growth rates at low nutrient concentrations because it supports higher substrate affinities per transport proteomic cost, whereas PTS achieves higher growth rates at high nutrient concentrations because it supports higher maximal uptake rates per transport proteomic cost.
doi: https://doi.org/10.1371/journal.pcbi.1009023.g005