Abstract

Mitochondria have specialised ribosomes that have diverged greatly from their bacterial and cytoplasmic counterparts. We have solved the structure of the large subunit from the yeast mitochondrial ribosome using single particle cryo-electron microscopy (cryo-EM) to an overall resolution of 3.2 Angstroms. A nearly complete atomic model has been built de novo and refined and consists of a total of 39 proteins, 13 of which are unique to yeast mitochondrial ribosomes, as well as many expansions of ribosomal RNA . The structure reveals a new exit tunnel path and architecture, unique elements of the ribosomal E site and a putative membrance-facing protuberance. The talk will also describe new tools that were developed for the interpretation, refinement and validation of cryo-EM density maps at high resolution.