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-Structure paper
タイトル | Cryo-EM captures a unique conformational rearrangement in 23S rRNA helices of the Mycobacterium 50S subunit. |
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ジャーナル・号・ページ | Int J Biol Macromol, Vol. 253, Issue Pt 3, Page 126876, Year 2023 |
掲載日 | 2023年12月31日 |
![]() | Priya Baid / Jayati Sengupta / ![]() |
PubMed 要旨 | Structural investigations of the ribosomes isolated from pathogenic and non-pathogenic Mycobacterium species have identified several mycobacteria-specific structural features of ribosomal RNA and ...Structural investigations of the ribosomes isolated from pathogenic and non-pathogenic Mycobacterium species have identified several mycobacteria-specific structural features of ribosomal RNA and proteins. Here, we report structural evidence of a hitherto unknown conformational switch of mycobacterium 23S rRNA helices (H54a and H67-H71). Cryo-electron microscopy (cryo-EM) structures (~3-4 Å) of the M. smegmatis (Msm) log-phase 50S ribosomal subunit revealed conformational variability in H67-H71 region of the 23S rRNA, and manifested that, while H68 possesses the usual stretched conformation in one class of the maps, another one exhibits a bulge-out, fused density of H68-H69 at the inter-subunit surface, indicating an intrinsic dynamics of these rRNA helices. Remarkably, altered conformation of H68 forming a more prominent bulge-out structure at the inter-subunit surface of the 50S subunit due to the conformational rearrangements of 23S rRNA H67-H71 region was clearly visualized in a 3 Å cryo-EM map of the 50S subunit obtained from the stationary phase ribosome dataset. The Msm50S subunit having such bulge-out conformation at the intersubunit surface would be incompatible for associating with the 30S subunit due to its inability to form major inter-subunit bridges. Evidently, availability of active 70S ribosome pool can be modulated by stabilizing either one of the H68 conformation. |
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手法 | EM (単粒子) |
解像度 | 3.5 - 4.1 Å |
構造データ | EMDB-33096, PDB-7xam: EMDB-33599, PDB-7y41: |
化合物 | ![]() ChemComp-MG: ![]() ChemComp-ZN: |
由来 |
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![]() | RIBOSOME / 50S Subunit / Domain IV of 23S rRNA / Alternate conformation / Helix 68 / Mycobacterium 50S subunit / Log Phase |