6ZM6

Human mitochondrial ribosome in complex with mRNA, A/A tRNA and P/P tRNA

This is a non-PDB format compatible entry.

Summary for 6ZM6

• Entry DOI: 10.2210/pdb6zm6/pdb
• EMDB information: 11279
• Descriptor: 16S mitochondrial rRNA, 39S ribosomal protein L14, mitochondrial, 39S ribosomal protein L15, mitochondrial, ... (94 entities in total)
• Functional Keywords: mitochondrion, translation, closed nascent-polypeptide tunnel, ribosome
• Biological source: Homo sapiens (Human); More
• Total number of polymer chains: 92
• Total formula weight: 3069299.32

Authors

Itoh, Y.,Andrell, J.,Amunts, A. (deposition date: 2020-07-01, release date: 2021-01-13, Last modification date: 2023-11-15)

Primary citation

Itoh, Y.,Andrell, J.,Choi, A.,Richter, U.,Maiti, P.,Best, R.B.,Barrientos, A.,Battersby, B.J.,Amunts, A.
Mechanism of membrane-tethered mitochondrial protein synthesis.
Science, 371:846-849, 2021

PubMed Abstract: Mitochondrial ribosomes (mitoribosomes) are tethered to the mitochondrial inner membrane to facilitate the cotranslational membrane insertion of the synthesized proteins. We report cryo-electron microscopy structures of human mitoribosomes with nascent polypeptide, bound to the insertase oxidase assembly 1-like (OXA1L) through three distinct contact sites. OXA1L binding is correlated with a series of conformational changes in the mitoribosomal large subunit that catalyze the delivery of newly synthesized polypeptides. The mechanism relies on the folding of mL45 inside the exit tunnel, forming two specific constriction sites that would limit helix formation of the nascent chain. A gap is formed between the exit and the membrane, making the newly synthesized proteins accessible. Our data elucidate the basis by which mitoribosomes interact with the OXA1L insertase to couple protein synthesis and membrane delivery.

PubMed: 33602856
DOI: 10.1126/science.abe0763

Experimental method

ELECTRON MICROSCOPY (2.59 Å)