ジャーナル: Elife / 年: 2020 タイトル: A processive rotary mechanism couples substrate unfolding and proteolysis in the ClpXP degradation machinery. 著者: Zev A Ripstein / Siavash Vahidi / Walid A Houry / John L Rubinstein / Lewis E Kay / 要旨: The ClpXP degradation machine consists of a hexameric AAA+ unfoldase (ClpX) and a pair of heptameric serine protease rings (ClpP) that unfold, translocate, and subsequently degrade client proteins. ...The ClpXP degradation machine consists of a hexameric AAA+ unfoldase (ClpX) and a pair of heptameric serine protease rings (ClpP) that unfold, translocate, and subsequently degrade client proteins. ClpXP is an important target for drug development against infectious diseases. Although structures are available for isolated ClpX and ClpP rings, it remains unknown how symmetry mismatched ClpX and ClpP work in tandem for processive substrate translocation into the ClpP proteolytic chamber. Here, we present cryo-EM structures of the substrate-bound ClpXP complex from at 2.3 to 3.3 Å resolution. The structures allow development of a model in which the sequential hydrolysis of ATP is coupled to motions of ClpX loops that lead to directional substrate translocation and ClpX rotation relative to ClpP. Our data add to the growing body of evidence that AAA+ molecular machines generate translocating forces by a common mechanism.
詳細: Buffer pH was measured as 8.2 at room temperature corresponding to a pH of 8.5 at 4 degrees, the temperature at which the complex was held before vitrification
グリッド
モデル: Homemade / 材質: COPPER/RHODIUM / メッシュ: 400 / 支持フィルム - トポロジー: HOLEY / 支持フィルム - Film thickness: 30 / 前処理 - タイプ: GLOW DISCHARGE / 前処理 - 時間: 15 sec. / 前処理 - 雰囲気: AIR / 詳細: Home-made gold grids were inspected before use
凍結
凍結剤: ETHANE-PROPANE / チャンバー内湿度: 100 % / チャンバー内温度: 277 K / 装置: FEI VITROBOT MARK III / 詳細: Blotted for 15 seconds at an offset of -5 mm.