ジャーナル: Mol Cell / 年: 2008 タイトル: Mechanism of gate opening in the 20S proteasome by the proteasomal ATPases. 著者: Julius Rabl / David M Smith / Yadong Yu / Shih-Chung Chang / Alfred L Goldberg / Yifan Cheng / 要旨: Substrates enter the cylindrical 20S proteasome through a gated channel that is regulated by the ATPases in the 19S regulatory particle in eukaryotes or the homologous PAN ATPase complex in archaea. ...Substrates enter the cylindrical 20S proteasome through a gated channel that is regulated by the ATPases in the 19S regulatory particle in eukaryotes or the homologous PAN ATPase complex in archaea. These ATPases contain a conserved C-terminal hydrophobic-tyrosine-X (HbYX) motif that triggers gate opening upon ATP binding. Using cryo-electron microscopy, we identified the sites in the archaeal 20S where PAN's C-terminal residues bind and determined the structures of the gate in its closed and open forms. Peptides containing the HbYX motif bind to 20S in the pockets between neighboring alpha subunits where they interact with conserved residues required for gate opening. This interaction induces a rotation in the alpha subunits and displacement of a reverse-turn loop that stabilizes the open-gate conformation. This mechanism differs from that of PA26/28, which lacks the HbYX motif and does not cause alpha subunit rotation. These findings demonstrated how the ATPases' C termini function to facilitate substrate entry.
モード: BRIGHT FIELD / 倍率(公称値): 50000 X / 倍率(補正後): 51159 X / 最大 デフォーカス(公称値): -3500 nm / 最小 デフォーカス(公称値): -1500 nm / Cs: 2 mm
試料ホルダ
温度: 90 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
画像スキャン
デジタル画像の数: 267
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解析
EMソフトウェア
名称: FREALIGN / カテゴリ: 3次元再構成
CTF補正
詳細: PHASE AND AMPLITUDE
対称性
点対称性: D7 (2回x7回 2面回転対称)
3次元再構成
手法: FOURIER SPACE / 解像度: 6.8 Å / 粒子像の数: 41546 / ピクセルサイズ(公称値): 1.4 Å / ピクセルサイズ(実測値): 1.37 Å / 倍率補正: YES 詳細: GENERATED BY DOCKING THE ATOMIC STRUCTURE OF T. ACIDOPHILUM 20S (1PMA) INTO SINGLE PARTICLE CRYOEM 3D RECONSTRUCTION. TOGETHER WITH THE OPEN GATE (3C91), IT SHOWS THE CONFORMATIONAL CHANGE ...詳細: GENERATED BY DOCKING THE ATOMIC STRUCTURE OF T. ACIDOPHILUM 20S (1PMA) INTO SINGLE PARTICLE CRYOEM 3D RECONSTRUCTION. TOGETHER WITH THE OPEN GATE (3C91), IT SHOWS THE CONFORMATIONAL CHANGE BETWEEN CLOSED AND OPEN GATE. 対称性のタイプ: POINT
原子モデル構築
プロトコル: RIGID BODY FIT / 空間: REAL / Target criteria: CROSS CORRELATION 詳細: METHOD--USING PROGRAM MAVE IN UPPSALA SOFTWARE FACTOR REFINEMENT PROTOCOL--RIGID BODY FITTING