ジャーナル: Nat Commun / 年: 2024 タイトル: Cryo-EM structures of the human Elongator complex at work. 著者: Nour-El-Hana Abbassi / Marcin Jaciuk / David Scherf / Pauline Böhnert / Alexander Rau / Alexander Hammermeister / Michał Rawski / Paulina Indyka / Grzegorz Wazny / Andrzej Chramiec-Głąbik ...著者: Nour-El-Hana Abbassi / Marcin Jaciuk / David Scherf / Pauline Böhnert / Alexander Rau / Alexander Hammermeister / Michał Rawski / Paulina Indyka / Grzegorz Wazny / Andrzej Chramiec-Głąbik / Dominika Dobosz / Bozena Skupien-Rabian / Urszula Jankowska / Juri Rappsilber / Raffael Schaffrath / Ting-Yu Lin / Sebastian Glatt / 要旨: tRNA modifications affect ribosomal elongation speed and co-translational folding dynamics. The Elongator complex is responsible for introducing 5-carboxymethyl at wobble uridine bases (cmU) in ...tRNA modifications affect ribosomal elongation speed and co-translational folding dynamics. The Elongator complex is responsible for introducing 5-carboxymethyl at wobble uridine bases (cmU) in eukaryotic tRNAs. However, the structure and function of human Elongator remain poorly understood. In this study, we present a series of cryo-EM structures of human ELP123 in complex with tRNA and cofactors at four different stages of the reaction. The structures at resolutions of up to 2.9 Å together with complementary functional analyses reveal the molecular mechanism of the modification reaction. Our results show that tRNA binding exposes a universally conserved uridine at position 33 (U), which triggers acetyl-CoA hydrolysis. We identify a series of conserved residues that are crucial for the radical-based acetylation of U and profile the molecular effects of patient-derived mutations. Together, we provide the high-resolution view of human Elongator and reveal its detailed mechanism of action.