National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
R01GM136936
米国
Robert A. Welch Foundation
H-2032-20200401
米国
引用
ジャーナル: Nat Commun / 年: 2022 タイトル: Compact IF2 allows initiator tRNA accommodation into the P site and gates the ribosome to elongation. 著者: Ritwika S Basu / Michael B Sherman / Matthieu G Gagnon / 要旨: During translation initiation, initiation factor 2 (IF2) holds initiator transfer RNA (fMet-tRNA) in a specific orientation in the peptidyl (P) site of the ribosome. Upon subunit joining IF2 ...During translation initiation, initiation factor 2 (IF2) holds initiator transfer RNA (fMet-tRNA) in a specific orientation in the peptidyl (P) site of the ribosome. Upon subunit joining IF2 hydrolyzes GTP and, concomitant with inorganic phosphate (P) release, changes conformation facilitating fMet-tRNA accommodation into the P site and transition of the 70 S ribosome initiation complex (70S-IC) to an elongation-competent ribosome. The mechanism by which IF2 separates from initiator tRNA at the end of translation initiation remains elusive. Here, we report cryo-electron microscopy (cryo-EM) structures of the 70S-IC from Pseudomonas aeruginosa bound to compact IF2-GDP and initiator tRNA. Relative to GTP-bound IF2, rotation of the switch 2 α-helix in the G-domain bound to GDP unlocks a cascade of large-domain movements in IF2 that propagate to the distal tRNA-binding domain C2. The C2-domain relocates 35 angstroms away from tRNA, explaining how IF2 makes way for fMet-tRNA accommodation into the P site. Our findings provide the basis by which IF2 gates the ribosome to the elongation phase.
EMPIAR-11012 (タイトル: Pseudomonas aeruginosa 70S ribosome initiation complex bound to compact IF2 Data size: 1.7 TB Data #1: Unaligned multiframe micrographs of the Pseudomonas aeruginosa 70S ribosome initiation complex bound to IF2 collected on Gatan K3 in Super Resolution [micrographs - multiframe])
全体 : Focused map of the N2 sub-domain of IF2 bound to the 30S subunit ...
全体
名称: Focused map of the N2 sub-domain of IF2 bound to the 30S subunit in the 70S ribosome initiation complex
要素
複合体: Focused map of the N2 sub-domain of IF2 bound to the 30S subunit in the 70S ribosome initiation complex
タンパク質・ペプチド: Translation initiation factor IF-2
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超分子 #1: Focused map of the N2 sub-domain of IF2 bound to the 30S subunit ...
超分子
名称: Focused map of the N2 sub-domain of IF2 bound to the 30S subunit in the 70S ribosome initiation complex タイプ: complex / ID: 1 / 親要素: 0 / 含まれる分子: all
タイプ: MAXIMUM LIKELIHOOD / ソフトウェア - 名称: cryoSPARC (ver. 3.1.0)
最終 角度割当
タイプ: MAXIMUM LIKELIHOOD / ソフトウェア - 名称: cryoSPARC (ver. 3.1.0)
最終 3次元分類
ソフトウェア - 名称: cryoSPARC (ver. 3.1.0)
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原子モデル構築 1
精密化
空間: REAL / プロトコル: RIGID BODY FIT
得られたモデル
PDB-7uiu: N2 sub-domain of IF2 bound to the 30S subunit in the Pseudomonas aeruginosa 70S ribosome initiation complex (focused classification and refinement)