Summary for 9K0Z
Entry DOI | 10.2210/pdb9k0z/pdb |
EMDB information | 61959 |
Descriptor | P/P-site Phe-tRNA(Phe), Small ribosomal subunit protein uS5, Small ribosomal subunit protein bS6, ... (62 entities in total) |
Functional Keywords | mycobacterium 70s ribosome, stationary phase, elongation factor g2, non-canonical factor, ribosome |
Biological source | Mycolicibacterium smegmatis MC2 155 More |
Total number of polymer chains | 58 |
Total formula weight | 2325323.25 |
Authors | |
Primary citation | Baid, P.,Sengupta, J. Cryo-EM structural analyses reveal a unique role for elongation factor G2 (EF-G2) in Mycobacteria. Febs J., 2025 Cited by PubMed Abstract: The gene-encoding translation elongation factor G (EF-G) has undergone gene duplication across various bacterial species including Mycobacteria, and in mammalian mitochondria, leading to the emergence of the paralogue elongation factor G2 (EF-G2). Our study reveals that mycobacterial EF-G2, unlike EF-G1, neither participates in ribosome-recycling nor significantly contributes to overall translation, suggesting that it plays an alternative role in Mycobacteria. Remarkably, our investigation found a significant overexpression of mycobacterial EF-G2 during the stationary growth phase. Moreover, EF-G2 lacks ribosome-dependent GTPase activity, an observation consistent with previous reports. Cryo-EM analysis of the M. smegmatis 70S ribosome purified from the nutrient-starved (stationary) phase and complexed with EF-G2 unveiled the structural basis for its inability to hydrolyse GTP in a ribosome-dependent manner. Furthermore, we report an unprecedented binding mode of two EF-G2 copies on the 50S ribosomal subunit that impedes subunit association, thereby preventing the formation of active 70S ribosomes. Thus, instead of performing canonical functions, mycobacterial EF-G2 acts as a translation repressor during nutrient starvation. Altogether, our findings shed light on the multifaceted mechanisms by which EF-G2 modulates protein synthesis under nutrient-limited conditions, providing insights into adaptive strategies employed by Mycobacteria to survive in hostile environments. PubMed: 40569974DOI: 10.1111/febs.70161 PDB entries with the same primary citation |
Experimental method | ELECTRON MICROSCOPY (4.7 Å) |
Structure validation
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