Species-dependence of the redox potential of the primary quinone electron acceptor QA in photosystem II verified by spectroelectrochemistry

Tadao Shibamoto, Yuki Kato, Ryo Nagao, Takuya Yamazaki, Tatsuya Tomo, Tadashi Watanabe

Research output: Contribution to journalArticlepeer-review

24 Citations (Scopus)


The redox potentials Em(QA/QA-) of the primary quinone electron acceptor QA in oxygen-evolving photosystem II complexes of three species were determined by spectroelectrochemistry. The Em(QA/QA-) values were experimentally found to be -162±3mV for a higher plant spinach, -171±3mV for a green alga Chlamydomonas reinhardtii and -104±4mV vs. SHE for a red alga Cyanidioschyzon merolae. On the basis of possible deviations for the experimental values, as estimated to differ by 9-29mV from each true value, plausible causes for such remarkable species-dependence of Em(QA/QA-) are discussed, mainly by invoking the effects of extrinsic subunits on the delicate structural environment around QA.

Original languageEnglish
Pages (from-to)1526-1530
Number of pages5
JournalFEBS Letters
Issue number8
Publication statusPublished - Apr 2010
Externally publishedYes


  • Electron transfer
  • Photosynthesis
  • Photosystem II
  • Primary quinone electron acceptor Q
  • Redox potential
  • Spectroelectrochemistry

ASJC Scopus subject areas

  • Biophysics
  • Structural Biology
  • Biochemistry
  • Molecular Biology
  • Genetics
  • Cell Biology


Dive into the research topics of 'Species-dependence of the redox potential of the primary quinone electron acceptor Q<sub>A</sub> in photosystem II verified by spectroelectrochemistry'. Together they form a unique fingerprint.

Cite this