ジャーナル: Nature / 年: 2010 タイトル: Coupled chaperone action in folding and assembly of hexadecameric Rubisco. 著者: Cuimin Liu / Anna L Young / Amanda Starling-Windhof / Andreas Bracher / Sandra Saschenbrecker / Bharathi Vasudeva Rao / Karnam Vasudeva Rao / Otto Berninghausen / Thorsten Mielke / F Ulrich ...著者: Cuimin Liu / Anna L Young / Amanda Starling-Windhof / Andreas Bracher / Sandra Saschenbrecker / Bharathi Vasudeva Rao / Karnam Vasudeva Rao / Otto Berninghausen / Thorsten Mielke / F Ulrich Hartl / Roland Beckmann / Manajit Hayer-Hartl / 要旨: Form I Rubisco (ribulose 1,5-bisphosphate carboxylase/oxygenase), a complex of eight large (RbcL) and eight small (RbcS) subunits, catalyses the fixation of atmospheric CO(2) in photosynthesis. The ...Form I Rubisco (ribulose 1,5-bisphosphate carboxylase/oxygenase), a complex of eight large (RbcL) and eight small (RbcS) subunits, catalyses the fixation of atmospheric CO(2) in photosynthesis. The limited catalytic efficiency of Rubisco has sparked extensive efforts to re-engineer the enzyme with the goal of enhancing agricultural productivity. To facilitate such efforts we analysed the formation of cyanobacterial form I Rubisco by in vitro reconstitution and cryo-electron microscopy. We show that RbcL subunit folding by the GroEL/GroES chaperonin is tightly coupled with assembly mediated by the chaperone RbcX(2). RbcL monomers remain partially unstable and retain high affinity for GroEL until captured by RbcX(2). As revealed by the structure of a RbcL(8)-(RbcX(2))(8) assembly intermediate, RbcX(2) acts as a molecular staple in stabilizing the RbcL subunits as dimers and facilitates RbcL(8) core assembly. Finally, addition of RbcS results in RbcX(2) release and holoenzyme formation. Specific assembly chaperones may be required more generally in the formation of complex oligomeric structures when folding is closely coupled to assembly.
詳細: Quantifoil grids (3/3) with 2 nm carbon on top
凍結
凍結剤: ETHANE / チャンバー内湿度: 95 % / チャンバー内温度: 85 K / 装置: OTHER / 詳細: Vitrification instrument: Vitrobot 手法: 10 second blotting before plunging, used 2 layers of filter paper
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電子顕微鏡法
顕微鏡
FEI TECNAI 12
温度
平均: 95 K
撮影
カテゴリ: CCD / フィルム・検出器のモデル: FEI EAGLE (2k x 2k) / デジタル化 - サンプリング間隔: 3.308 µm / 平均電子線量: 20 e/Å2 / 詳細: Data collected on CCD / ビット/ピクセル: 16