Escherichia colirobustly expresses ATP synthase at growth rate maximizing concentrations

Abstract

Improved protein expression is an important evolutionary adaptation of bacteria. A key question is whether evolution has led to optimal protein expression that maximizes immediate growth rate (short-term fitness) across conditions. Alternatively, fitter genetic variants could display suboptimal short-term fitness, because they cannot do better or because they strive for long-term fitness maximization by, for instance, anticipating future conditions. To answer this question, we focus on the ATP-producing enzyme F1F0 H+-ATPase, which is an abundant enzyme and ubiquitously expressed across conditions. We tested the optimality of H+-ATPase expression in Escherichia coli across 27 different nutrient conditions. In all tested conditions, wild-type E. coli expresses its H+- ATPase remarkably close to optimal concentrations that maximize immediate growth rate. This work indicates that bacteria can achieve robust optimal protein expression for immediate growth-rate.

Trade‐offs between the instantaneous growth rate and long‐term fitness: Consequences for microbial physiology and predictive computational models

“…Indeed, significant evidence exists that expression of metabolic proteins in E. coli (and other bacteria) is close to 'optimal' under conditions of nutrient excess, in the sense that any deviation from the observed wild-type expression results in a decrease of the instantaneous growth rate. [35,[42][43][44][45][46][47][48]…”

“…That is, metabolic proteins often exhibit expression levels such that the instantaneous growth rate is maximized under the studied growth condition. [35,[42][43][44][45][46][47][48][49][50] For example, it was recently shown that E. coli expresses its F 1 F 0 -ATPase, a protein complex that uses the proton-motive force to regenerates ATP, at optimal levels across more than 25 conditions. [43] Figure 2 exemplifies the effect of modulating F 1 F 0 -ATPase expression on the growth rate for growth on glucose, showing that the WT growth rate indeed corresponds to the growth rate of the mutant with optimal F 1 F 0 -ATPase expression.…”

“…[35,[42][43][44][45][46][47][48][49][50] For example, it was recently shown that E. coli expresses its F 1 F 0 -ATPase, a protein complex that uses the proton-motive force to regenerates ATP, at optimal levels across more than 25 conditions. [43] Figure 2 exemplifies the effect of modulating F 1 F 0 -ATPase expression on the growth rate for growth on glucose, showing that the WT growth rate indeed corresponds to the growth rate of the mutant with optimal F 1 F 0 -ATPase expression. Keren et al [44] studied the expression of over eighty different proteins in S. cerevisiae under a single growth condition, and showed that they too were optimally expressed.…”

“…Error bars indicate the standard deviation. Data sourced from, [43] see the original publication for experimental methods and analysis of 26 different carbon sources.…”