Macromolecular Message Translation The ribosome is a macromolecular machine that translates the sequence of messenger RNA into proteins in all living cells. Structures of prokaryotic ribosomes have supplied insight into the conserved features of such protein synthesis; however, eukaryotic translation has additional levels of complexity. Ben-Shem et al. (p. 1203 ) have determined the crystal structure of the yeast 80S ribosome at 4.15 angstrom resolution. The ribosome is in a ratcheted conformation, which is a state that is an intermediate in the translocation of messenger RNA and transfer RNA. The crystal structure provides the molecular underpinning for existing biochemical and genetic data and will inform the design of functional experiments.