Protein L5 is crucial for in vivo assembly of the bacterial 50S ribosomal subunit central protuberance

Nucleic Acids Res. 2012 Oct;40(18):9153-9. doi: 10.1093/nar/gks676. Epub 2012 Jul 20.


In the present work, ribosomes assembled in bacterial cells in the absence of essential ribosomal protein L5 were obtained. After arresting L5 synthesis, Escherichia coli cells divide a limited number of times. During this time, accumulation of defective large ribosomal subunits occurs. These 45S particles lack most of the central protuberance (CP) components (5S rRNA and proteins L5, L16, L18, L25, L27, L31, L33 and L35) and are not able to associate with the small ribosomal subunit. At the same time, 5S rRNA is found in the cytoplasm in complex with ribosomal proteins L18 and L25 at quantities equal to the amount of ribosomes. Thus, it is the first demonstration that protein L5 plays a key role in formation of the CP during assembly of the large ribosomal subunit in the bacterial cell. A possible model for the CP assembly in vivo is discussed in view of the data obtained.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Escherichia coli / genetics
  • Escherichia coli / growth & development
  • Escherichia coli Proteins / genetics
  • Escherichia coli Proteins / physiology*
  • Gene Deletion
  • Models, Molecular
  • RNA, Ribosomal, 5S / chemistry
  • Ribosomal Proteins / chemistry
  • Ribosomal Proteins / genetics
  • Ribosomal Proteins / physiology*
  • Ribosome Subunits, Large, Bacterial / chemistry*
  • Ribosome Subunits, Large, Bacterial / metabolism
  • Ribosomes / metabolism


  • Escherichia coli Proteins
  • RNA, Ribosomal, 5S
  • Ribosomal Proteins
  • RplE protein, E coli
  • ribosomal protein L5