Composition of the mitoribosome of Diplonema papillatum

Biosynthesis of mitochondrial genome-encoded proteins is carried out by the mitoribosome, a specialized apparatus that has evolved and diverged dramatically since its bacterial origin. Recent studies across various eukaryotes have demonstrated widespread structural and compositional diversity of mitoribosomes. We used affinity pulldown of four mitoribosomal proteins to carry out a detailed analysis of mitoribosomes in Diplonema papillatum, the type species of diplonemids, a widespread group of single-celled marine flagellates. Using as baits mitoribosomal proteins integrating at distinct sites and phases during subunit maturation also allowed us to sample populations of mitoribosome assembly intermediates.