EMD-33599

Single-particle
4.1 Å
EMD-33599 Deposition: 13/06/2022
Map released: 03/05/2023
Last modified: 15/05/2024
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links

EMD-33599

Mycobacterium smegmatis 50S ribosomal subunit from Log Phase of growth

EMD-33599

Single-particle
4.1 Å
EMD-33599 Deposition: 13/06/2022
Map released: 03/05/2023
Last modified: 15/05/2024
Overview 3D View Sample Experiment Validation Volume Browser Additional data Links
Sample Organism: Mycolicibacterium smegmatis MC2 155
Sample: Mycobacterium smegmatis 50S ribosomal subunit from Log Phase of growth
Fitted models: 7y41 (Avg. Q-score: 0.422)

Deposition Authors: Sengupta J, Baid P
Cryo-EM captures a unique conformational rearrangement in 23S rRNA helices of the Mycobacterium 50S subunit.
Baid P, Sengupta J
(2023) Int J Biol Macromol , 253 , 126876 - 126876
PUBMED: 37709237
DOI: doi:10.1016/j.ijbiomac.2023.126876
ISSN: 0141-8130
ASTM: IJBMDR
Abstract:
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.