EMD-11278
Human mitochondrial ribosome in complex with OXA1L, mRNA, A/A tRNA, P/P tRNA and nascent polypeptide
EMD-11278
Single-particle2.89 Å
Deposition: 01/07/2020
Map released: 13/01/2021
Last modified: 15/11/2023
Sample Organism:
Homo sapiens
Sample: Translating ribosome with insertase
Fitted models: 6zm5 (Avg. Q-score: 0.552)
Deposition Authors: Itoh Y , Andrell J
Sample: Translating ribosome with insertase
Fitted models: 6zm5 (Avg. Q-score: 0.552)
Deposition Authors: Itoh Y , Andrell J
Mechanism of membrane-tethered mitochondrial protein synthesis.
Itoh Y ,
Andrell J ,
Choi A ,
Richter U ,
Maiti P ,
Best RB ,
Barrientos A ,
Battersby BJ ,
Amunts A
(2021) Science , 371 , 846 - 849
(2021) Science , 371 , 846 - 849
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.
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.