Crystal structure of the PsbP protein of photosystem II from Nicotiana tabacum

EMBO Rep. 2004 Apr;5(4):362-7. doi: 10.1038/sj.embor.7400113. Epub 2004 Mar 12.


PsbP is a membrane-extrinsic subunit of the water-oxidizing complex photosystem II (PS II). The evolutionary origin of PsbP has long been a mystery because it specifically exists in higher plants and green algae but not in cyanobacteria. We report here the crystal structure of PsbP from Nicotiana tabacum at a resolution of 1.6 A. Its structure is mainly composed of beta-sheet, and is not similar to any structures in cyanobacterial PS II. However, the electrostatic surface potential of PsbP is similar to that of cyanobacterial PsbV (cyt c(550)), which has a function similar to PsbP. A structural homology search with the DALI algorithm indicated that the folding of PsbP is very similar to that of Mog1p, a regulatory protein for the nuclear transport of Ran GTPase. The structure of PsbP provides insight into its novel function in GTP-regulated metabolism in PS II.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Crystallography, X-Ray
  • Cyanobacteria / chemistry
  • Molecular Sequence Data
  • Nuclear Proteins / chemistry
  • Photosystem II Protein Complex / chemistry*
  • Protein Structure, Secondary
  • Protein Structure, Tertiary
  • Saccharomyces cerevisiae / chemistry
  • Saccharomyces cerevisiae Proteins
  • Sequence Alignment
  • Static Electricity
  • Tobacco / chemistry*
  • ran GTP-Binding Protein / chemistry


  • Nuclear Proteins
  • Photosystem II Protein Complex
  • Saccharomyces cerevisiae Proteins
  • MOG1 protein, S cerevisiase
  • ran GTP-Binding Protein