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-Structure paper
Title | Dual Functions of a Rubisco Activase in Metabolic Repair and Recruitment to Carboxysomes. |
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Journal, issue, pages | Cell, Vol. 183, Issue 2, Page 457-473.e20, Year 2020 |
Publish date | Oct 15, 2020 |
![]() | Mirkko Flecken / Huping Wang / Leonhard Popilka / F Ulrich Hartl / Andreas Bracher / Manajit Hayer-Hartl / ![]() |
PubMed Abstract | 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. |
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Methods | EM (single particle) / X-ray diffraction |
Resolution | 1.38 - 8.2 Å |
Structure data | EMDB-11028, PDB-6z1f: EMDB-11029, PDB-6z1g: ![]() EMDB-11575: ![]() PDB-6has: ![]() PDB-6z1d: ![]() PDB-6z1e: |
Chemicals | ![]() ChemComp-NI: ![]() ChemComp-HOH: ![]() ChemComp-GD: ![]() ChemComp-CL: ![]() ChemComp-ADP: ![]() ChemComp-AGS: ![]() ChemComp-MG: ![]() ChemComp-CAP: |
Source |
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![]() | CHAPERONE / alpha-beta structure / Rubisco / AAA+ domain / AAA+ / beta barrel / PHOTOSYNTHESIS |