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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. Mitoribosomes, like cytoplasmic ribosomes, consist of two subunits — large (mtLSU) and small (mt-SSU). However, the ratio of rRNA/protein is different from cytoplasmic ribosomes, mitoribosomes consist of several specific proteins and less rRNAs.
Contents
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. Proteins that are the key components in electron transport chain are translated in ribosomes
Structure
Mammalian mitoribosome has small 28S and large 39S subunits, together forming a 55S mitoribosome.