Structure of the green algal photosystem I supercomplex with a decameric light-harvesting complex I

Michihiro Suga, Shin Ichiro Ozawa, Kaori Yoshida-Motomura, Fusamichi Akita, Naoyuki Miyazaki, Yuichiro Takahashi

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

In plants and green algae, the core of photosystem I (PSI) is surrounded by a peripheral antenna system consisting of light-harvesting complex I (LHCI). Here we report the cryo-electron microscopic structure of the PSI–LHCI supercomplex from the green alga Chlamydomonas reinhardtii. The structure reveals that eight Lhca proteins form two tetrameric LHCI belts attached to the PsaF side while the other two Lhca proteins form an additional Lhca2/Lhca9 heterodimer attached to the opposite side. The spatial arrangement of light-harvesting pigments reveals that Chlorophylls b are more abundant in the outer LHCI belt than in the inner LHCI belt and are absent from the core, thereby providing the downhill energy transfer pathways to the PSI core. PSI–LHCI is complexed with a plastocyanin on the patch of lysine residues of PsaF at the luminal side. The assembly provides a structural basis for understanding the mechanism of light-harvesting, excitation energy transfer of the PSI–LHCI supercomplex and electron transfer with plastocyanin.

Original languageEnglish
Pages (from-to)626-636
Number of pages11
JournalNature Plants
Volume5
Issue number6
DOIs
Publication statusPublished - Jun 1 2019

ASJC Scopus subject areas

  • Plant Science

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