Mitochondrial ribosome

A diagram showing mtDNA (circular) and mitochondrial ribosomes among other mitochondria structures

Mitochondrial ribosome or mitoribosome is a protein complex that is active in mitochondria and functions as a riboprotein for translating mitochondrial mRNAs encoded in mtDNA. Mitoribosome, like cytoplasmatic ribosome, consists of two subunits — large (mtLSU) and small (mt-SSU).[1] However, the ratio of rRNA/protein is different from cytoplasmic ribosome, mitoribosome consists of several specific proteins and less rRNAs.[1]

Function

Mitochondria contain around 1000 proteins in yeast and 1500 proteins in human organisms, however only 8 and 13 proteins are encoded in mtDNA in yeast and human, respectively. Most of mitochondria proteins are synthesized via cytoplasmic ribosomes.[2] Proteins that are the key components in electron transport chain are translated in ribosomes[3][4]

Structure

Mammalian mitoribosome has small 28S and large 39S subunits, together forming a 55S mitoribosome.[5]

References

  1. 1 2 Alexey Amunts, Alan Brown, Jaan Toots, Sjors H. W. Scheres & V. Ramakrishnan (2015). "Ribosome. The structure of the human mitochondrial ribosome". Science. 348 (6230): 95–98. doi:10.1126/science.aaa1193. PMC 4501431Freely accessible. PMID 25838379.
  2. ↑ Wenz, Lena-Sophie; Opaliński, Łukasz; Wiedemann, Nils; Becker, Thomas (2015). "Cooperation of protein machineries in mitochondrial protein sorting". Biochimica et Biophysica Acta (BBA) - Molecular Cell Research. 1853 (5): 1119–1129. doi:10.1016/j.bbamcr.2015.01.012. ISSN 0167-4889.
  3. ↑ Johnston, Iain G.; Williams, Ben P. (2016). "Evolutionary Inference across Eukaryotes Identifies Specific Pressures Favoring Mitochondrial Gene Retention". Cell Systems. 2: 101–111. doi:10.1016/j.cels.2016.01.013. ISSN 2405-4712.
  4. ↑ Hamers, Laurel (2016). "Why do our cell's power plants have their own DNA?". Science. doi:10.1126/science.aaf4083. ISSN 0036-8075.
  5. ↑ Basil J. Greber, Philipp Bieri, Marc Leibundgut, Alexander Leitner, Ruedi Aebersold, Daniel Boehringer & Nenad Ban (2015). "Ribosome. The complete structure of the 55S mammalian mitochondrial ribosome". Science. 348 (6232): 303–308. doi:10.1126/science.aaa3872. PMID 25837512.


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