2WVW: Cryo-em Structure of the Rbcl-rbcx Complex

Citation:
Abstract
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.
PDB ID: 2WVWDownload
MMDB ID: 79388
PDB Deposition Date: 2009/10/20
Updated in MMDB: 2011/08 
Experimental Method:
electron microscopy
Resolution: 9  Å
Source Organism:
Synechococcus elongatus PCC 6301
Similar Structures:
Biological Unit for 2WVW: 24-meric; determined by author and by software (PQS)
Molecular Components in 2WVW
Label Count Molecule
Proteins (24 molecules)
16
Rbcx Protein
Molecule annotation
8
Ribulose Bisphosphate Carboxylase Large Chain
Molecule annotation
* Click molecule labels to explore molecular sequence information.

Citing MMDB
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