Fig. 3: A density maintenance theory quantitatively predicts scaling between surface-to-volume ratio (SA/V) and proteome allocation towards ribosomes ϕrib.
From: Maintenance of cytoplasmic and membrane densities shapes cellular geometry in Escherichia coli
a The density maintenance theory as derived in the text with the density ratio κ, membrane proteome partition ψmem, periplasmic proteome partition ψperi, and RNA/protein ratio βϕrib highlighted in red, blue, purple, and gold, respectively. b The empirical linear (approximately constant) relationship between membrane proteome partition and ribosomal proteome allocation. c The empirical exponential relationship between periplasmic proteome partition and ribosomal proteome allocation. d Predicted scaling of surface-to-volume SA/V on the ribosomal proteome allocation ϕrib for different values of the density ratio κ (gray lines). Green curves correspond to the fit of Eq. (4) to our data, using the empirical relationships shown in b and c. Lines correspond to the mean value of the posterior predictive distribution. Shaded bands correspond to the 95% (pale, approximately 2σ) and 68% (light, approximately 1σ) credible regions of the posterior predictive distribution for each quantity. White-faced points correspond to our direct measurements of allocation parameters via mass spectrometry and SA/V via microscopy. All biological replicates are shown.
