3ZW6

Structure of Green-Type Rubisco Activase from Tobacco

(2011) Nat Struct Mol Biol 18: 1366

• PubMed: 22056769 Search on PubMed
• DOI: https://doi.org/10.1038/nsmb.2171
• Primary Citation of Related Structures:  
  3T15, 3ZW6


• PubMed Abstract: 
  

  Rubisco, the enzyme that catalyzes the fixation of atmospheric CO(2) in photosynthesis, is subject to inactivation by inhibitory sugar phosphates. Here we report the 2.95-Å crystal structure of Nicotiana tabacum Rubisco activase (Rca), the enzyme that facilitates the removal of these inhibitors. Rca from tobacco has a classical AAA(+)-protein domain architecture. Although Rca populates a range of oligomeric states when in solution, it forms a helical arrangement with six subunits per turn when in the crystal. However, negative-stain electron microscopy of the active mutant R294V suggests that Rca functions as a hexamer. The residues determining species specificity for Rubisco are located in a helical insertion of the C-terminal domain and probably function in conjunction with the N-domain in Rubisco recognition. Loop segments exposed toward the central pore of the hexamer are required for the ATP-dependent remodeling of Rubisco, resulting in the release of inhibitory sugar.

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Organizational Affiliation: 

Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Martinsried, Germany.