Fig. 2
Dissecting ribosomal particles from different organisms and organelles by bottom-up and top-down LC-MS/MS analyses. a–c Relative quantification of both ribosomal and non-ribosomal proteins present in the preparations of So70S, Hs40S, and Hs60S ribosomal particles, respectively. Protein abundance was estimated by using the intensity-based absolute quantification (iBAQ) values of each identified protein. d–f Top-down LC-MS/MS base peak chromatograms of all proteins in the So70S, Hs40S, and Hs60S ribosomal particles, respectively. Top-down LC-MS/MS analysis allows for identification of both ribosomal and non-ribosomal proteins and their distinct proteoforms. g Relative abundance distributions of proteoforms detected in ribosomal proteins of the 40S and 60S subunit identified by database searching. Each dot represents a proteoform of the gene products listed on the x-axis with increasing size representing increasing relative abundance. The position of the dots along the y-axis shows the deviation of measured mass of the proteoform from the mass calculated from the amino acid sequence. Several commonly occurring post-translational modifications (e.g., acetylation, phosphorylation) are annotated with their corresponding mass shift. The data point for L14 is missing since the observed mass shifts introduced by a varying number of inserted alanine repeats is outside the scale of the plot (namely: +213 and +355 Da). To stay consistent, we adopted the ribosomal protein names from Uniprot entries. The pictograms of the Vitruvian man were prepared based on an image that was obtained under a CC0 license from https://commons.wikimedia.org/wiki/File:Digisapiens.png
