9psm | pdb_00009psm

In situ structure of the human mitoribosome in the A/P-P/E state

spinqualitylabelsall models 9psm, resolution 2.98Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 9psm is a 10 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Electron Microscopy, Resolution 2.98Å Ligands: 1MA, 2MG, 5MC, 5MU, ACE, ATP, B8T, FES, GDP, K, MA6, MG, NAD, OMG, OMU, PSU, PUT, SPD, SPM, VAL, ZN Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed Translation elongation is a universally conserved step in protein synthesis, relying on elongation factors that engage the ribosomal L7/L12 stalk to mediate aminoacyl-tRNA delivery, accommodation, and ribosomal translocation. Using in organello cryo-electron microscopy, we reveal how the mitochondrial translation accelerator TACO1 promotes efficient elongation on human mitoribosomes. TACO1 binds the mitoribosomal region typically bound by elongation factor Tu (mtEF-Tu), bridging the large and small subunits via contacts with 16S rRNA, bL12m, A-site tRNA, and uS12m. While active throughout elongation, TACO1 is especially critical when translating polyproline motifs. Its absence prolongs mtEF-Tu residence in A/T states, causes persistent mitoribosomal stalling and premature subunit dissociation. Structural analyses indicate that TACO1 competes with mtEF-Tu for mitoribosome binding, stabilizes A-site tRNA, and enhances peptidyl transfer through a mechanism distinct from EF-P and eIF5A. These findings suggest that bacterial TACO1 orthologs may serve analogous roles, highlighting an evolutionarily conserved strategy for maintaining elongation efficiency during challenging translation events. Structural basis of TACO1-mediated efficient mitochondrial translation.,Wang S, Brischigliaro M, Zhang Y, Wu C, Zheng W, Barrientos A, Xiong Y Nat Commun. 2026 Feb 9. doi: 10.1038/s41467-026-69156-y. PMID:41663403 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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