Structural adaptation of the plant protease Deg1 to repair photosystem II during light exposure

Nat Struct Mol Biol. 2011 Jun;18(6):728-31. doi: 10.1038/nsmb.2055. Epub 2011 May 1.


Deg1 is a chloroplastic protease involved in maintaining the photosynthetic machinery. Structural and biochemical analyses reveal that the inactive Deg1 monomer is transformed into the proteolytically active hexamer at acidic pH. The change in pH is sensed by His244, which upon protonation, repositions a specific helix to trigger oligomerization. This system ensures selective activation of Deg1 during daylight, when acidification of the thylakoid lumen occurs and photosynthetic proteins are damaged.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / enzymology*
  • Arabidopsis / radiation effects
  • Arabidopsis Proteins / chemistry*
  • Arabidopsis Proteins / metabolism*
  • Crystallography, X-Ray
  • Hydrogen-Ion Concentration
  • Light*
  • Models, Biological
  • Models, Molecular
  • Photosystem II Protein Complex / metabolism*
  • Protein Conformation
  • Protein Multimerization
  • Protein Structure, Quaternary
  • Protein Structure, Tertiary
  • Serine Endopeptidases / chemistry*
  • Serine Endopeptidases / metabolism*


  • Arabidopsis Proteins
  • Photosystem II Protein Complex
  • Deg1 protein, Arabidopsis
  • Serine Endopeptidases