9HCC

Mouse mitoribosome large subunit assembly intermediate (without uL16m) bound to MRM3-dimer, DDX28 and the MALSU-L0R8F8-mt-ACP complex, State A1 (SAMC knock-out)

This is a non-PDB format compatible entry.

Summary for 9HCC

• Entry DOI: 10.2210/pdb9hcc/pdb
• EMDB information: 52044
• Descriptor: 16S rRNA (1584-MER), Large ribosomal subunit protein uL14m, Large ribosomal subunit protein uL15m, ... (52 entities in total)
• Functional Keywords: mitochondria, ribosome, large subunit, assembly intermediate
• Biological source: Mus musculus (house mouse); More
• Total number of polymer chains: 51
• Total formula weight: 1833629.49

Authors

Singh, V.,Rorbach, J.,Freyer, C.,Amunts, A.,Wredenberg, A. (deposition date: 2024-11-08, release date: 2025-06-18, Last modification date: 2025-07-16)

Primary citation

Glasgow, R.I.C.,Singh, V.,Pena-Perez, L.,Wilhalm, A.,Moedas, M.F.,Moore, D.,Rosenberger, F.A.,Li, X.,Atanassov, I.,Saba, M.,Cipullo, M.,Rorbach, J.,Wedell, A.,Freyer, C.,Amunts, A.,Wredenberg, A.
The mitochondrial methylation potential gates mitoribosome assembly.
Nat Commun, 16:5388-5388, 2025

PubMed Abstract: S-adenosylmethionine (SAM) is the principal methyl donor in cells and is essential for mitochondrial gene expression, influencing RNA modifications, translation, and ribosome biogenesis. Using direct long-read RNA sequencing in mouse tissues and embryonic fibroblasts, we show that processing of the mitochondrial ribosomal gene cluster fails in the absence of mitochondrial SAM, leading to an accumulation of unprocessed precursors. Proteomic analysis of ribosome fractions revealed these precursors associated with processing and assembly factors, indicating stalled biogenesis. Structural analysis by cryo-electron microscopy demonstrated that SAM-dependent methylation is required for peptidyl transferase centre formation during mitoribosome assembly. Our findings identify a critical role for SAM in coordinating mitoribosomal RNA processing and large subunit maturation, linking cellular methylation potential to mitochondrial translation capacity.

PubMed: 40562754
DOI: 10.1038/s41467-025-60977-x

Experimental method

ELECTRON MICROSCOPY (5.67 Å)