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-Structure paper
タイトル | Loss of a single methylation in 23S rRNA delays 50S assembly at multiple late stages and impairs translation initiation and elongation. |
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ジャーナル・号・ページ | Proc Natl Acad Sci U S A, Vol. 117, Issue 27, Page 15609-15619, Year 2020 |
掲載日 | 2020年7月7日 |
著者 | Wei Wang / Wanqiu Li / Xueliang Ge / Kaige Yan / Chandra Sekhar Mandava / Suparna Sanyal / Ning Gao / |
PubMed 要旨 | Ribosome biogenesis is a complex process, and dozens of factors are required to facilitate and regulate the subunit assembly in bacteria. The 2'-O-methylation of U2552 in 23S rRNA by ...Ribosome biogenesis is a complex process, and dozens of factors are required to facilitate and regulate the subunit assembly in bacteria. The 2'-O-methylation of U2552 in 23S rRNA by methyltransferase RrmJ is a crucial step in late-stage assembly of the 50S subunit. Its absence results in severe growth defect and marked accumulation of pre50S assembly intermediates. In the present work, we employed cryoelectron microscopy to characterize a set of late-stage pre50S particles isolated from an Δ strain. These assembly intermediates (solved at 3.2 to 3.8 Å resolution) define a collection of late-stage particles on a progressive assembly pathway. Apart from the absence of L16, L35, and L36, major structural differences between these intermediates and the mature 50S subunit are clustered near the peptidyl transferase center, such as H38, H68-71, and H89-93. In addition, the ribosomal A-loop of the mature 50S subunit from Δ strain displays large local flexibility on nucleotides next to unmethylated U2552. Fast kinetics-based biochemical assays demonstrate that the Δ 50S subunit is only 50% active and two times slower than the WT 50S subunit in rapid subunit association. While the Δ 70S ribosomes show no defect in peptide bond formation, peptide release, and ribosome recycling, they translocate with 20% slower rate than the WT ribosomes in each round of elongation. These defects amplify during synthesis of the full-length proteins and cause overall defect in protein synthesis. In conclusion, our data reveal the molecular roles of U2552 methylation in both ribosome biogenesis and protein translation. |
リンク | Proc Natl Acad Sci U S A / PubMed:32571953 / PubMed Central |
手法 | EM (単粒子) |
解像度 | 3.14 - 3.64 Å |
構造データ | EMDB-30212: EMDB-30213: EMDB-30214: EMDB-30215, PDB-7bv8: |
由来 |
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キーワード | RIBOSOME / ribosome assembly / ribosome biogenesis |