fusA mutations prevent translational misreading in the presence of apramycin. Cells were treated with Apr (16 µM) at 0.25 OD₆₀₀ and cell growth was recorded photometically. Peptides with missense errors in the abundant cytosolic protein EF-Tu were quantified by targeted MS using label-free Parallel Reaction Monitoring (PRM). Bars represent the mean ± SD of 3 technical replicates of median error frequencies of at least 25 indenpendent misreading events. Note that untreated wt and mutant are indistiguishable

Figure S7A: Representative elution profile of missense peptides fragments detected by PRM. 

Error E308D in EF-Tu was quantified in the untreated and and Apr-treated (16 µM) cells. Missense peptide candidates are validated by matching their MS/MS spectra with in-silico predicted fragmentation spectra. Established fragmentation pattern and chromatographic retention times are used to target missense peptides across various biological states. Peptide abundances are calculated by integrating the signal of their co-eluting peptide fragments and error frequencies are estimated as the ratio of missense peptide and correct peptides abundances (see Methods).