ジャーナル: Cell / 年: 2020 タイトル: Dual Functions of a Rubisco Activase in Metabolic Repair and Recruitment to Carboxysomes. 著者: Mirkko Flecken / Huping Wang / Leonhard Popilka / F Ulrich Hartl / Andreas Bracher / Manajit Hayer-Hartl / 要旨: Rubisco, the key enzyme of CO fixation in photosynthesis, is prone to inactivation by inhibitory sugar phosphates. Inhibited Rubisco undergoes conformational repair by the hexameric AAA+ chaperone ...Rubisco, the key enzyme of CO fixation in photosynthesis, is prone to inactivation by inhibitory sugar phosphates. Inhibited Rubisco undergoes conformational repair by the hexameric AAA+ chaperone Rubisco activase (Rca) in a process that is not well understood. Here, we performed a structural and mechanistic analysis of cyanobacterial Rca, a close homolog of plant Rca. In the Rca:Rubisco complex, Rca is positioned over the Rubisco catalytic site under repair and pulls the N-terminal tail of the large Rubisco subunit (RbcL) into the hexamer pore. Simultaneous displacement of the C terminus of the adjacent RbcL opens the catalytic site for inhibitor release. An alternative interaction of Rca with Rubisco is mediated by C-terminal domains that resemble the small Rubisco subunit. These domains, together with the N-terminal AAA+ hexamer, ensure that Rca is packaged with Rubisco into carboxysomes. The cyanobacterial Rca is a dual-purpose protein with functions in Rubisco repair and carboxysome organization.
凍結剤: ETHANE / チャンバー内湿度: 90 % / チャンバー内温度: 298 K / 装置: FEI VITROBOT MARK IV
詳細
NosRubisco (1 uM) was incubated with NaHCO3 (10 mM) at 298 K for 10 min followed by addition of CABP (8 uM). CABP-inhibited NosRubisco (0.5 uM) was then incubated with NosRcaDC (10 uM) in the presence of ATP (2 mM) for 10 s, followed by the addition of ATP-gammaS (2 mM), and incubated at 298 K for another 10 min before preparing the cryo-grids.
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電子顕微鏡法
顕微鏡
FEI TITAN KRIOS
撮影
フィルム・検出器のモデル: GATAN K3 (6k x 4k) / 撮影したグリッド数: 1 / 実像数: 9042 / 平均露光時間: 2.8 sec. / 平均電子線量: 60.0 e/Å2 / 詳細: 31 frames per image