7PUB

Late assembly intermediate of the Trypanosoma brucei mitoribosomal small subunit

This is a non-PDB format compatible entry.

Summary for 7PUB

• Entry DOI: 10.2210/pdb7pub/pdb
• EMDB information: 13661
• Descriptor: 9S rRNA, uS14m, uS15m, ... (83 entities in total)
• Functional Keywords: mitoribosome, assembly intermediate, trypanosoma brucei, small subunit, mt-ssu, ssu, ribosome
• Biological source: Trypanosoma brucei brucei; More
• Total number of polymer chains: 76
• Total formula weight: 3617428.02

Authors

Lenarcic, T.,Leibundgut, M.,Saurer, M.,Ramrath, D.J.F.,Fluegel, T.,Boehringer, D.,Ban, N. (deposition date: 2021-09-29, release date: 2022-05-04, Last modification date: 2024-11-20)

Primary citation

Lenarcic, T.,Niemann, M.,Ramrath, D.J.F.,Calderaro, S.,Flugel, T.,Saurer, M.,Leibundgut, M.,Boehringer, D.,Prange, C.,Horn, E.K.,Schneider, A.,Ban, N.
Mitoribosomal small subunit maturation involves formation of initiation-like complexes.
Proc.Natl.Acad.Sci.USA, 119:-, 2022

PubMed Abstract: Mitochondrial ribosomes (mitoribosomes) play a central role in synthesizing mitochondrial inner membrane proteins responsible for oxidative phosphorylation. Although mitoribosomes from different organisms exhibit considerable structural variations, recent insights into mitoribosome assembly suggest that mitoribosome maturation follows common principles and involves a number of conserved assembly factors. To investigate the steps involved in the assembly of the mitoribosomal small subunit (mt-SSU) we determined the cryoelectron microscopy structures of middle and late assembly intermediates of the mitochondrial small subunit (mt-SSU) at 3.6- and 3.7-Å resolution, respectively. We identified five additional assembly factors that together with the mitochondrial initiation factor 2 (mt-IF-2) specifically interact with functionally important regions of the rRNA, including the decoding center, thereby preventing premature mRNA or large subunit binding. Structural comparison of assembly intermediates with mature mt-SSU combined with RNAi experiments suggests a noncanonical role of mt-IF-2 and a stepwise assembly process, where modular exchange of ribosomal proteins and assembly factors together with mt-IF-2 ensure proper 9S rRNA folding and protein maturation during the final steps of assembly.

PubMed: 35042777
DOI: 10.1073/pnas.2114710118

Experimental method

ELECTRON MICROSCOPY (3.7 Å)