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.
構造決定の手法: 多波長異常分散 / 解像度: 1.38→30 Å / Cor.coef. Fo:Fc: 0.971 / Cor.coef. Fo:Fc free: 0.961 / SU B: 2.553 / SU ML: 0.045 / SU R Cruickshank DPI: 0.0671 / 交差検証法: THROUGHOUT / σ(F): 0 / ESU R: 0.067 / ESU R Free: 0.061 詳細: HYDROGENS HAVE BEEN ADDED IN THE RIDING POSITIONS U VALUES : REFINED INDIVIDUALLY