PH-Sensing Machinery of Excitation Energy Transfer in Diatom PSI-FCPI Complexes

Ryo Nagao, Makio Yokono, Yoshifumi Ueno, Jian Ren Shen, Seiji Akimoto

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11 Citations (Scopus)


Excitation energy-transfer processes in photosynthetic light-harvesting complexes are strongly affected by the surrounding environments of pigments. Here we report on the effects of pH changes on excitation energy dynamics in both diatom photosystem I-fucoxanthin chlorophyll a/c-binding protein (PSI-FCPI) and PSI core complexes by means of fluorescence spectroscopies. The steady-state fluorescence spectra of the PSI-FCPI showed similar features among three samples at pH 5.0, 6.5, and 8.0. However, fluorescence decay-associated spectra of the pH 5.0- and 8.0-adapted PSI-FCPI within 100 ps exhibit peak shifts to longer and shorter wavelengths, respectively, than the peaks in the pH 6.5 spectra. Because such spectral changes hardly occur in the PSI complexes, the peak shifts at pH 5.0 and 8.0 in the PSI-FCPI can be ascribed to alterations of pigment-pigment and/or pigment-protein interactions around/within FCPI caused by the pH changes. These findings provide novel physical insights into the pH-sensing light-harvesting strategy in diatom PSI-FCPI.

Original languageEnglish
Pages (from-to)3531-3535
Number of pages5
JournalJournal of Physical Chemistry Letters
Issue number13
Publication statusPublished - Jul 5 2019

ASJC Scopus subject areas

  • General Materials Science
  • Physical and Theoretical Chemistry


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