Crystal structure of redox-sensitive phosphoribulokinase (PRK) from the green algae Chlamydomonas reinhardtii

Experimental Data Snapshot

  • Resolution: 2.60 Å
  • R-Value Free: 0.262 
  • R-Value Work: 0.227 
  • R-Value Observed: 0.229 

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ArabidopsisandChlamydomonasphosphoribulokinase crystal structures complete the redox structural proteome of the Calvin-Benson cycle.

Gurrieri, L.Del Giudice, A.Demitri, N.Falini, G.Pavel, N.V.Zaffagnini, M.Polentarutti, M.Crozet, P.Marchand, C.H.Henri, J.Trost, P.Lemaire, S.D.Sparla, F.Fermani, S.

(2019) Proc Natl Acad Sci U S A 116: 8048-8053

  • DOI: https://doi.org/10.1073/pnas.1820639116
  • Primary Citation of Related Structures:  
    6H7G, 6H7H

  • PubMed Abstract: 

    In land plants and algae, the Calvin-Benson (CB) cycle takes place in the chloroplast, a specialized organelle in which photosynthesis occurs. Thioredoxins (TRXs) are small ubiquitous proteins, known to harmonize the two stages of photosynthesis through a thiol-based mechanism. Among the 11 enzymes of the CB cycle, the TRX target phosphoribulokinase (PRK) has yet to be characterized at the atomic scale. To accomplish this goal, we determined the crystal structures of PRK from two model species: the green alga Chlamydomonas reinhardtii ( Cr PRK) and the land plant Arabidopsis thaliana ( At PRK). PRK is an elongated homodimer characterized by a large central β-sheet of 18 strands, extending between two catalytic sites positioned at its edges. The electrostatic surface potential of the catalytic cavity has both a positive region suitable for binding the phosphate groups of substrates and an exposed negative region to attract positively charged TRX-f. In the catalytic cavity, the regulatory cysteines are 13 Å apart and connected by a flexible region exclusive to photosynthetic eukaryotes-the clamp loop-which is believed to be essential for oxidation-induced structural rearrangements. Structural comparisons with prokaryotic and evolutionarily older PRKs revealed that both At PRK and Cr PRK have a strongly reduced dimer interface and an increased number of random-coiled regions, suggesting that a general loss in structural rigidity correlates with gains in TRX sensitivity during the molecular evolution of PRKs in eukaryotes.

  • Organizational Affiliation

    Elettra-Sincrotrone Trieste, 34149 Basovizza, Trieste, Italy.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Phosphoribulokinase, chloroplastic
A, B
346Chlamydomonas reinhardtiiMutation(s): 0 
Gene Names: PRKA
Find proteins for P19824 (Chlamydomonas reinhardtii)
Explore P19824 
Go to UniProtKB:  P19824
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP19824
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.60 Å
  • R-Value Free: 0.262 
  • R-Value Work: 0.227 
  • R-Value Observed: 0.229 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 77.679α = 90
b = 83.549β = 90
c = 133.146γ = 90
Software Package:
Software NamePurpose
XDSdata reduction
Aimlessdata scaling

Structure Validation

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Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
ItalyFARB2012-University of Bologna

Revision History  (Full details and data files)

  • Version 1.0: 2019-04-10
    Type: Initial release
  • Version 1.1: 2019-04-17
    Changes: Data collection, Database references
  • Version 1.2: 2019-04-24
    Changes: Data collection, Database references
  • Version 1.3: 2024-01-17
    Changes: Data collection, Database references, Refinement description