9G5B

Assembly intermediate of human mitochondrial ribosome small subunit (State A)

Summary for 9G5B

• Entry DOI: 10.2210/pdb9g5b/pdb
• EMDB information: 51053 51083
• Descriptor: 28S ribosomal protein S34, mitochondrial, 28S ribosomal protein S7, mitochondrial, 28S ribosomal protein S9, mitochondrial, ... (37 entities in total)
• Functional Keywords: mitochondrial ribosomal small subunit, assembly intermediate, mtg3, single-particle cryo-em, ribosome
• Biological source: Homo sapiens (human); More
• Total number of polymer chains: 32
• Total formula weight: 1265302.69

Authors

Finke, A.F.,Heinrichs, M.,Aibara, S.,Richter-Dennerlein, R.,Hillen, H.S. (deposition date: 2024-07-16, release date: 2025-04-23, Last modification date: 2025-04-30)

Primary citation

Heinrichs, M.,Finke, A.F.,Aibara, S.,Krempler, A.,Boshnakovska, A.,Rehling, P.,Hillen, H.S.,Richter-Dennerlein, R.
Coupling of ribosome biogenesis and translation initiation in human mitochondria.
Nat Commun, 16:3641-3641, 2025

PubMed Abstract: Biogenesis of mitoribosomes requires dedicated chaperones, RNA-modifying enzymes, and GTPases, and defects in mitoribosome assembly lead to severe mitochondriopathies in humans. Here, we characterize late-step assembly states of the small mitoribosomal subunit (mtSSU) by combining genetic perturbation and mutagenesis analysis with biochemical and structural approaches. Isolation of native mtSSU biogenesis intermediates via a FLAG-tagged variant of the GTPase MTG3 reveals three distinct assembly states, which show how factors cooperate to mature the 12S rRNA. In addition, we observe four distinct primed initiation mtSSU states with an incompletely matured rRNA, suggesting that biogenesis and translation initiation are not mutually exclusive processes but can occur simultaneously. Together, these results provide insights into mtSSU biogenesis and suggest a functional coupling between ribosome biogenesis and translation initiation in human mitochondria.

PubMed: 40240327
DOI: 10.1038/s41467-025-58827-x

Experimental method

ELECTRON MICROSCOPY (3.2 Å)