8CBM

Structure of human mitochondrial CCA-adding enzyme in complex with mitochondrial pre-tRNA-Ile

Summary for 8CBM

• Entry DOI: 10.2210/pdb8cbm/pdb
• Related: 8CBK 8CBL
• EMDB information: 16545 16690 16691
• Descriptor: 3-hydroxyacyl-CoA dehydrogenase type-2, CCA tRNA nucleotidyltransferase 1, mitochondrial, tRNA methyltransferase 10 homolog C, ... (8 entities in total)
• Functional Keywords: rna maturation, rna modification, mitochondrial trna, rna methyltransferase, mrpp1, mrpp2, mrpp3, rna binding protein, m6a, rna binding, rna recognition
• Biological source: Homo sapiens (human); More
• Total number of polymer chains: 7
• Total formula weight: 226364.61

Authors

MEYNIER, V.,HARDWICK, S.,CATALA, M.,ROSKE, J.,OERUM, S.,CHIRGADZE, D.,BARRAUD, P.,LUISI, B.,TISNE, C. (deposition date: 2023-01-25, release date: 2024-06-12)

Primary citation

Meynier, V.,Hardwick, S.W.,Catala, M.,Roske, J.J.,Oerum, S.,Chirgadze, D.Y.,Barraud, P.,Yue, W.W.,Luisi, B.F.,Tisne, C.
Structural basis for human mitochondrial tRNA maturation.
Nat Commun, 15:4683-4683, 2024

PubMed Abstract: The human mitochondrial genome is transcribed into two RNAs, containing mRNAs, rRNAs and tRNAs, all dedicated to produce essential proteins of the respiratory chain. The precise excision of tRNAs by the mitochondrial endoribonucleases (mt-RNase), P and Z, releases all RNA species from the two RNA transcripts. The tRNAs then undergo 3'-CCA addition. In metazoan mitochondria, RNase P is a multi-enzyme assembly that comprises the endoribonuclease PRORP and a tRNA methyltransferase subcomplex. The requirement for this tRNA methyltransferase subcomplex for mt-RNase P cleavage activity, as well as the mechanisms of pre-tRNA 3'-cleavage and 3'-CCA addition, are still poorly understood. Here, we report cryo-EM structures that visualise four steps of mitochondrial tRNA maturation: 5' and 3' tRNA-end processing, methylation and 3'-CCA addition, and explain the defined sequential order of the tRNA processing steps. The methyltransferase subcomplex recognises the pre-tRNA in a distinct mode that can support tRNA-end processing and 3'-CCA addition, likely resulting from an evolutionary adaptation of mitochondrial tRNA maturation complexes to the structurally-fragile mitochondrial tRNAs. This subcomplex can also ensure a tRNA-folding quality-control checkpoint before the sequential docking of the maturation enzymes. Altogether, our study provides detailed molecular insight into RNA-transcript processing and tRNA maturation in human mitochondria.

PubMed: 38824131
DOI: 10.1038/s41467-024-49132-0

Experimental method

ELECTRON MICROSCOPY (3.14 Å)