TY - JOUR
T1 - PH-Sensing Machinery of Excitation Energy Transfer in Diatom PSI-FCPI Complexes
AU - Nagao, Ryo
AU - Yokono, Makio
AU - Ueno, Yoshifumi
AU - Shen, Jian Ren
AU - Akimoto, Seiji
N1 - Publisher Copyright:
© 2019 American Chemical Society.
PY - 2019/7/5
Y1 - 2019/7/5
N2 - 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.
AB - 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.
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U2 - 10.1021/acs.jpclett.9b01314
DO - 10.1021/acs.jpclett.9b01314
M3 - Article
C2 - 31192608
AN - SCOPUS:85067928918
VL - 10
SP - 3531
EP - 3535
JO - Journal of Physical Chemistry Letters
JF - Journal of Physical Chemistry Letters
SN - 1948-7185
IS - 13
ER -