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-Structure paper
タイトル | Structure of a mitochondrial ribosome with fragmented rRNA in complex with membrane-targeting elements. |
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ジャーナル・号・ページ | Nat Commun, Vol. 13, Issue 1, Page 6132, Year 2022 |
掲載日 | 2022年10月17日 |
著者 | Victor Tobiasson / Ieva Berzina / Alexey Amunts / |
PubMed 要旨 | 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 Å ...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 Å 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. |
リンク | Nat Commun / PubMed:36253367 / PubMed Central |
手法 | EM (単粒子) |
解像度 | 2.91 - 3.2 Å |
構造データ | EMDB-15100, PDB-8a22: EMDB-15576, PDB-8apn: EMDB-15577, PDB-8apo: |
化合物 | ChemComp-MG: ChemComp-K: ChemComp-ZN: ChemComp-ATP: ChemComp-HOH: |
由来 |
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キーワード | RIBOSOME / mitoribosome / mitochondria / polytomella / fragmentation / rrna / evolution / translation |