9K0Z

EF-G2 bound 70S ribosome complex of M. smegmatis

これはPDB形式変換不可エントリーです。

9K0Z の概要

• エントリーDOI: 10.2210/pdb9k0z/pdb
• EMDBエントリー: 61959
• 分子名称: P/P-site Phe-tRNA(Phe), Small ribosomal subunit protein uS5, Small ribosomal subunit protein bS6, ... (62 entities in total)
• 機能のキーワード: mycobacterium 70s ribosome, stationary phase, elongation factor g2, non-canonical factor, ribosome
• 由来する生物種: Mycolicibacterium smegmatis MC2 155; 詳細
• タンパク質・核酸の鎖数: 58
• 化学式量合計: 2325323.25

構造登録者

Sengupta, J.,Baid, P. (登録日: 2024-10-16, 公開日: 2025-07-09, 最終更新日: 2025-12-31)

主引用文献

Baid, P.,Sengupta, J.
Cryo-EM structural analyses reveal a unique role for elongation factor G2 (EF-G2) in Mycobacteria.
Febs J., 292:6533-6556, 2025

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: 40569974
DOI: 10.1111/febs.70161

実験手法

ELECTRON MICROSCOPY (4.7 Å)