8a22

Structure of the mitochondrial ribosome from Polytomella magna

spinqualitylabelsall models 8a22, resolution 2.91Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 8a22 is a 10 chain structure with sequence from Polytomella magna. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Electron Microscopy, Resolution 2.91Å Ligands: ATP, K, MG, ZN Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed Mitoribosomes of green algae display a great structural divergence from their tracheophyte relatives, with fragmentation of both rRNA and proteins as a defining feature. Here, we report a 2.9 A resolution structure of the mitoribosome from the alga Polytomella magna harbouring a reduced rRNA split into 13 fragments. We found that the rRNA contains a non-canonical reduced form of the 5S, as well as a permutation of the LSU domain I. The mt-5S rRNA is stabilised by mL40 that is also found in mitoribosomes lacking the 5S, which suggests an evolutionary pathway. Through comparison to other ribosomes with fragmented rRNAs, we observe that the pattern is shared across large evolutionary distances, and between cellular compartments, indicating an evolutionary convergence and supporting the concept of a primordial fragmented ribosome. On the protein level, eleven peripherally associated HEAT-repeat proteins are involved in the binding of 3' rRNA termini, and the structure features a prominent pseudo-trimer of one of them (mL116). Finally, in the exit tunnel, mL128 constricts the tunnel width of the vestibular area, and mL105, a homolog of a membrane targeting component mediates contacts with an inner membrane bound insertase. Together, the structural analysis provides insight into the evolution of the ribosomal machinery in mitochondria. Structure of a mitochondrial ribosome with fragmented rRNA in complex with membrane-targeting elements.,Tobiasson V, Berzina I, Amunts A Nat Commun. 2022 Oct 17;13(1):6132. doi: 10.1038/s41467-022-33582-5. PMID:36253367 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Ribosome 3D structures

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