Structural basis of redox modulation on chloroplast ATP synthase

Commun Biol. 2020 Sep 2;3(1):482. doi: 10.1038/s42003-020-01221-8.


In higher plants, chloroplast ATP synthase has a unique redox switch on its γ subunit that modulates enzyme activity to limit ATP hydrolysis at night. To understand the molecular details of the redox modulation, we used single-particle cryo-EM to determine the structures of spinach chloroplast ATP synthase in both reduced and oxidized states. The disulfide linkage of the oxidized γ subunit introduces a torsional constraint to stabilize the two β hairpin structures. Once reduced, free cysteines alleviate this constraint, resulting in a concerted motion of the enzyme complex and a smooth transition between rotary states to facilitate the ATP synthesis. We added an uncompetitive inhibitor, tentoxin, in the reduced sample to limit the flexibility of the enzyme and obtained high-resolution details. Our cryo-EM structures provide mechanistic insight into the redox modulation of the energy regulation activity of chloroplast ATP synthase.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Biocatalysis
  • Chloroplast Proton-Translocating ATPases / chemistry*
  • Chloroplast Proton-Translocating ATPases / metabolism*
  • Chloroplast Proton-Translocating ATPases / ultrastructure
  • Cryoelectron Microscopy
  • Light
  • Models, Biological
  • Models, Molecular
  • Nucleotides / metabolism
  • Oxidation-Reduction
  • Protein Domains
  • Protein Subunits / chemistry
  • Spinacia oleracea / enzymology*
  • Statistics as Topic
  • Structure-Activity Relationship


  • Nucleotides
  • Protein Subunits
  • Chloroplast Proton-Translocating ATPases