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Title | Mechanism of Enzyme Repair by the AAA Chaperone Rubisco Activase. |
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Journal, issue, pages | Mol Cell, Vol. 67, Issue 5, Page 744-756.e6, Year 2017 |
Publish date | Sep 7, 2017 |
Authors | Javaid Y Bhat / Goran Miličić / Gabriel Thieulin-Pardo / Andreas Bracher / Andrew Maxwell / Susanne Ciniawsky / Oliver Mueller-Cajar / John R Engen / F Ulrich Hartl / Petra Wendler / Manajit Hayer-Hartl / |
PubMed Abstract | How AAA+ chaperones conformationally remodel specific target proteins in an ATP-dependent manner is not well understood. Here, we investigated the mechanism of the AAA+ protein Rubisco activase (Rca) ...How AAA+ chaperones conformationally remodel specific target proteins in an ATP-dependent manner is not well understood. Here, we investigated the mechanism of the AAA+ protein Rubisco activase (Rca) in metabolic repair of the photosynthetic enzyme Rubisco, a complex of eight large (RbcL) and eight small (RbcS) subunits containing eight catalytic sites. Rubisco is prone to inhibition by tight-binding sugar phosphates, whose removal is catalyzed by Rca. We engineered a stable Rca hexamer ring and analyzed its functional interaction with Rubisco. Hydrogen/deuterium exchange and chemical crosslinking showed that Rca structurally destabilizes elements of the Rubisco active site with remarkable selectivity. Cryo-electron microscopy revealed that Rca docks onto Rubisco over one active site at a time, positioning the C-terminal strand of RbcL, which stabilizes the catalytic center, for access to the Rca hexamer pore. The pulling force of Rca is fine-tuned to avoid global destabilization and allow for precise enzyme repair. |
External links | Mol Cell / PubMed:28803776 |
Methods | EM (single particle) |
Resolution | 3.39 - 7.56 Å |
Structure data | EMDB-3699, PDB-5nv3: EMDB-3700: EMDB-3701: EMDB-3702: |
Chemicals | ChemComp-CAP: ChemComp-MG: |
Source |
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Keywords | LYASE / beta barrel |