FIG 1.

Persister cells synthesize proteins involved in essential physiological processes. (A) Transcription of plasmid-encoded hipA (pBAD33::hipA) was induced in E. coli K-12 strain MG1655 at an OD₆₀₀ of 0.4 for 3 h, followed by ampicillin treatment and addition of glucose to repress further hipA transcription. Approximately 20 h after hipA induction, the culture was sampled at 16 time points. Proteins were digested with endoproteinase Lys-C, and peptides were identified and quantified by LC-MS/MS. The growth curve is representative of three biological replicates. (B) Incorporation of Lys8 into proteins across 17 time points calculated from the measured protein H/L ratios. The box plots are representative of three biological replicates. (C) Heat map of all quantified proteins color coded based on their H/L ratio ranking within each time bin. Missing values are colored in white. KEGG pathway enrichment analysis of quanified proteins in the 25th percentile (top 25% [red]), 25th to 50th percentile (pink), 50th to 75th percentile (light red and blue), and 75th percentile (bottom 25% [blue]) across all time bins. The number of enriched proteins in each category is indicated outside the bars. (D to F) Label incorporation curves of selected examples of enzymes involved in protein degradation, translation, and folding (chaperones).