Evolution of the protein stoichiometry in the L12 stalk of bacterial and organellar ribosomes

Nat Commun. 2013;4:1387. doi: 10.1038/ncomms2373.


The emergence of ribosomes and translation factors is central for understanding the origin of life. Recruitment of translation factors to bacterial ribosomes is mediated by the L12 stalk composed of protein L10 and several copies of protein L12, the only multi-copy protein of the ribosome. Here we predict stoichiometries of L12 stalk for >1,200 bacteria, mitochondria and chloroplasts by a computational analysis, and validate the predictions by quantitative mass spectrometry. The majority of bacteria have L12 stalks allowing for binding of four or six copies of L12, largely independent of the taxonomic group or living conditions of the bacteria, whereas some cyanobacteria have eight copies. Mitochondrial and chloroplast ribosomes can accommodate six copies of L12. The last universal common ancestor probably had six molecules of L12 molecules bound to L10. Changes of the stalk composition provide a unique possibility to trace the evolution of protein components of the ribosome.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Bacteria / genetics
  • Bacteria / metabolism*
  • Bacterial Proteins / chemistry
  • Bacterial Proteins / genetics*
  • Bacterial Proteins / metabolism
  • Chloroplasts / metabolism
  • Evolution, Molecular*
  • Gene Dosage
  • Humans
  • Mass Spectrometry
  • Mitochondria / metabolism
  • Mitochondrial Proteins / chemistry
  • Mitochondrial Proteins / metabolism
  • Molecular Sequence Data
  • Phylogeny
  • Protein Binding
  • Protein Multimerization
  • Protein Structure, Secondary
  • Protein Structure, Tertiary
  • RNA, Ribosomal, 16S / genetics
  • Ribosomal Protein L10
  • Ribosomal Proteins / chemistry
  • Ribosomal Proteins / genetics*
  • Ribosomal Proteins / metabolism
  • Ribosomes / metabolism*
  • Synechococcus / metabolism
  • Thermotoga maritima / genetics
  • Thermotoga maritima / metabolism


  • Bacterial Proteins
  • Mitochondrial Proteins
  • RNA, Ribosomal, 16S
  • RPL10 protein, human
  • Ribosomal Proteins
  • ribosomal protein L7-L12