7NQH

55S mammalian mitochondrial ribosome with mtRF1a and P-site tRNAMet

This is a non-PDB format compatible entry.

Summary for 7NQH

• Entry DOI: 10.2210/pdb7nqh/pdb
• EMDB information: 12527
• Descriptor: Mitochondrial ribosomal protein L12, Mitochondrial ribosomal protein L10, Mitochondrial ribosomal protein L11, ... (94 entities in total)
• Functional Keywords: ribosome, mitochondria, termination, mtrf1a, release, translation
• Biological source: Homo sapiens (Human); More
• Total number of polymer chains: 93
• Total formula weight: 3121263.32

Authors

Kummer, E.,Schubert, K.,Ban, N. (deposition date: 2021-03-01, release date: 2021-05-05, Last modification date: 2024-10-16)

Primary citation

Kummer, E.,Schubert, K.N.,Schoenhut, T.,Scaiola, A.,Ban, N.
Structural basis of translation termination, rescue, and recycling in mammalian mitochondria.
Mol.Cell, 81:2566-2582.e6, 2021

PubMed Abstract: The mitochondrial translation system originates from a bacterial ancestor but has substantially diverged in the course of evolution. Here, we use single-particle cryo-electron microscopy (cryo-EM) as a screening tool to identify mitochondrial translation termination mechanisms and to describe them in molecular detail. We show how mitochondrial release factor 1a releases the nascent chain from the ribosome when it encounters the canonical stop codons UAA and UAG. Furthermore, we define how the peptidyl-tRNA hydrolase ICT1 acts as a rescue factor on mitoribosomes that have stalled on truncated messages to recover them for protein synthesis. Finally, we present structural models detailing the process of mitochondrial ribosome recycling to explain how a dedicated elongation factor, mitochondrial EFG2 (mtEFG2), has specialized for cooperation with the mitochondrial ribosome recycling factor to dissociate the mitoribosomal subunits at the end of the translation process.

PubMed: 33878294
DOI: 10.1016/j.molcel.2021.03.042

Experimental method

ELECTRON MICROSCOPY (3.5 Å)