Chinese Science Bulletin

, Volume 45, Issue 23, pp 2162–2168 | Cite as

Trichloroacetate affects the EPR Signal IIslow and Signal I in the thylakoid ofChlamydomonas reinhardtii

  • Yong Yu
  • Xinjian Yu
  • Jiyu Ye
  • Chunhe Xu
  • Govindjee


One electron paramagnetic resonance (EPR) signal, named Signal IIslow, originates from the oxidized Tyrosine 160 (YD) of D2 polypeptide of photosystem II reaction center. After adding high concentration trichloroacetate (TCA) to theChlamydomonas reinhardtii thylakoid suspension, this signal was abolished in a minute. Treatment of TCA also removes a few of polypeptides, including three extrinsic polypeptides of oxygen-evolving complex, from the thylakoid membrane. Based upon the analysis of the microenvironment around YD with a three-dimensional model, it is indicated that relatively high hydrophobicity of this microenvironment may be the essential prerequisite for TCA to affect YD. It has been observed that TCA treatment also retards the decay of the Signal 1, produced by the oxidized reaction center chlorophyll dimer (P700+) of photosystem I.


thylakoid YD EPR trichloroacetate (TCA) three-dimensional model 


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Copyright information

© Science in China Press 2000

Authors and Affiliations

  • Yong Yu
    • 1
  • Xinjian Yu
    • 1
  • Jiyu Ye
    • 1
  • Chunhe Xu
    • 1
  • Govindjee
    • 2
  1. 1.Shanghai Institute of Plant PhysiologyChinese Academy of SciencesShanghaiChina
  2. 2.Center of Biophysics & Computational BiologyUniversity of IllinoisUrbanaUSA

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