ジャーナル: Nat Struct Biol / 年: 2003 タイトル: Incorporation of aminoacyl-tRNA into the ribosome as seen by cryo-electron microscopy. 著者: Mikel Valle / Andrey Zavialov / Wen Li / Scott M Stagg / Jayati Sengupta / Rikke C Nielsen / Poul Nissen / Stephen C Harvey / Måns Ehrenberg / Joachim Frank / 要旨: Aminoacyl-tRNAs (aa-tRNAs) are delivered to the ribosome as part of the ternary complex of aa-tRNA, elongation factor Tu (EF-Tu) and GTP. Here, we present a cryo-electron microscopy (cryo-EM) study, ...Aminoacyl-tRNAs (aa-tRNAs) are delivered to the ribosome as part of the ternary complex of aa-tRNA, elongation factor Tu (EF-Tu) and GTP. Here, we present a cryo-electron microscopy (cryo-EM) study, at a resolution of approximately 9 A, showing that during the incorporation of the aa-tRNA into the 70S ribosome of Escherichia coli, the flexibility of aa-tRNA allows the initial codon recognition and its accommodation into the ribosomal A site. In addition, a conformational change observed in the GTPase-associated center (GAC) of the ribosomal 50S subunit may provide the mechanism by which the ribosome promotes a relative movement of the aa-tRNA with respect to EF-Tu. This relative rearrangement seems to facilitate codon recognition by the incoming aa-tRNA, and to provide the codon-anticodon recognition-dependent signal for the GTPase activity of EF-Tu. From these new findings we propose a mechanism that can explain the sequence of events during the decoding of mRNA on the ribosome.
モード: BRIGHT FIELD / 倍率(公称値): 50000 X / 倍率(補正後): 49696 X / 最大 デフォーカス(公称値): 4000 nm / 最小 デフォーカス(公称値): 2000 nm
試料ホルダ
温度: 93 K / 傾斜角・最大: 0 ° / 傾斜角・最小: 0 °
撮影
電子線照射量: 20 e/Å2 / フィルム・検出器のモデル: KODAK SO-163 FILM
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解析
EMソフトウェア
ID
名称
カテゴリ
1
O
モデルフィッティング
2
SPIDER
3次元再構成
CTF補正
詳細: CTF correction of 3D maps by Wiener filteration
対称性
点対称性: C1 (非対称)
3次元再構成
手法: 3D projection matching; conjugate gradient with regularization 解像度: 10 Å / 解像度の算出法: OTHER / 粒子像の数: 75996 / ピクセルサイズ(実測値): 2.82 Å / 倍率補正: TMV / 対称性のタイプ: POINT
原子モデル構築
プロトコル: OTHER / 空間: REAL / 詳細: METHOD--Manual fitting in O