Question

Mitochondrial ribosomes manufacture 13 proteins, all of which are components of the oxidative phosphorylation machinery. Propose an explanation why the peptide exit tunnel of the mitoribosome is lined with hydrophobic groups rather than hydrophilic groups, as in a cytoplasmic ribosome.

Short answer

Mitochondrial translation is organized in the context of respiratory chain assembly and speculates how the alteration of the ribosomal tunnel exit might allow the establishment of a subset of specialized ribososmes that individually organize the early steps in the biogenesis of distinct mitochondrially encoded proteins.

Step-by-step solution

Mitochondrial ribosomes

Mitochondrial ribosomes perform protein synthesis inside mitochondria, the organelles responsible for energy conversion and adenosine triphosphate generation in eukaryotic cells.

Explanation why the peptide exit tunnel of the mitoribosome is lined with hydrophobic groups rather than hydrophilic groups, as in a cytoplasmic ribosome

The ribosomal polypeptide tunnel exit is the site where a variety of factors interact with newly prepared proteins. In mitochondrial ribosomes, this site has been modified in the course of the evolution. Mitochondrial ribosomes are responsible for the preparation of a few hydrophobic membrane proteins that are the essential subunits of the mitochondrial respiratory chain.