Crystal structure of the eukaryotic 80S ribosome

The macromolecular assembly called the ribosome is responsible for protein biosynthesis following genetic instructions in all organisms, and composed of two unequal subunits, a small and a large subunit (40S and 60S in eukaryotes; 30S and 50S in prokaryotes). The full eukaryotic ribosome has a sedimentation coefficient of 80S and a minimal mass of ∼3.3 MDa (yeast, plants). The large 60S subunit consists of three ribosomal RNA (rRNA) molecules (28S, 5.8S, 5S) and 46 proteins whereas the small 40S subunit includes only one rRNA chain (18S) and harbors 33 proteins.