Enhancement of excitation-energy quenching in fucoxanthin chlorophyll a/c-binding proteins isolated from a diatom Phaeodactylum tricornutum upon excess-light illumination

Ryo Nagao, Makio Yokono, Yoshifumi Ueno, Takehiro Suzuki, Minoru Kumazawa, Ka Ho Kato, Naoki Tsuboshita, Naoshi Dohmae, Kentaro Ifuku, Jian Ren Shen, Seiji Akimoto

Research output: Contribution to journalArticlepeer-review

Abstract

Photosynthetic organisms regulate pigment composition and molecular oligomerization of light-harvesting complexes in response to solar light intensities, in order to improve light-harvesting efficiency. Here we report excitation-energy dynamics and relaxation of fucoxanthin chlorophyll a/c-binding protein (FCP) complexes isolated from a diatom Phaeodactylum tricornutum grown under high-light (HL) illumination. Two types of FCP complexes were prepared from this diatom under the HL condition, whereas one FCP complex was isolated from the cells grown under a low-light (LL) condition. The subunit composition and oligomeric states of FCP complexes under the HL condition are different from those under the LL condition. Absorption and fluorescence spectra at 77 K of the FCP complexes also vary between the two conditions, indicating modifications of the pigment composition and arrangement upon the HL illumination. Time-resolved fluorescence curves at 77 K of the FCP complexes under the HL condition showed shorter lifetime components compared with the LL condition. Fluorescence decay-associated spectra at 77 K showed distinct excitation-energy-quenching components and alterations of energy-transfer pathways in the FCP complexes under the HL condition. These findings provide insights into molecular and functional mechanisms of the dynamic regulation of FCPs in this diatom under excess-light conditions.

Original languageEnglish
Article number148350
JournalBiochimica et Biophysica Acta - Bioenergetics
Volume1862
Issue number2
DOIs
Publication statusPublished - Feb 1 2021

Keywords

  • Diatom
  • FCP
  • Phaeodactylum tricornutum
  • Photoinhibition
  • Time-resolved fluorescence

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Cell Biology

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