Fig. 1: Biogenesis of translation proteins in a PURE at threshold.
From: Autonomous biogenesis of all thirty proteins of the Escherichia coli translation machinery
a Schematic overview of the 30 protein factors and enzymes involved in protein translation, including initiation factors (IF), aminoacyl-tRNA synthetases (aaRS), elongation factors (EF), and release/recycling factors (RF). b Scheme illustrating the concept of gene expression with positive feedback from self-synthesis of translation proteins. c A PURE reactions with component at threshold concentrations, GFP expression is undetectable prior to biogenesis (i), but becomes detectable after the self-synthesis of translation machinery (ii), indicating functional activity of newly synthesized proteins. A PURE with saturating concentrations of all components shows indistinguishable GFP reporter expression before (iii) and after (iv) biogenesis. d Fluorescence intensity (FI) time traces of an eGFP reporter gene in a full PURE reaction with and without the genes of the translation proteins. Mean ± STD (n = 3). e Numerical simulation of AsnRS expression in PURE at different initial AsnRS concentrations. Max. synthesis rate vs. initial AsnRS0 for reactions with (biogenesis) and without (no biogenesis) functional nascent AsnRS. The gray band denotes the threshold regime, where rates are highly sensitive to small changes. f FI(t) and its second derivative, FI″(t), for PURE reactions at different initial ValRS concentrations with and without the ValRS gene. FI and FI″ are normalized to the maxima of a full PURE control. Dashed lines mark t = argmax FI″(t). g Peak synthesis rate (maximum of dFI/dt) as a function of initial ValRS concentration. Rates are normalized to the control maximum. Horizontal markers indicate means that are connected with a dotted line (n = 3 different and independent titration series, see Supplementary Fig. 7). h tmax is the time of max. FI″(t) as a function of ValRS from the same data as in (g). i Average normalized peak rate across all 30 translation proteins ± their genes at threshold (n = 3 independent experiments). A protein Pi is marked with an asterisk when purified Pi was added to kick-start biogenesis (Supplementary Table 1). Data is provided in the Source Data file.
