Molecular shape under far-red light and red light-induced association of Arabidopsis phytochrome B

Mao Oide, Takaaki Hikima, Tomotaka Oroguchi, Takayuki Kato, Yuhki Yamaguchi, Shizue Yoshihara, Masaki Yamamoto, Masayoshi Nakasako, Koji Okajima

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)


Phytochrome B (phyB) is a plant photoreceptor protein that regulates various photomorphogenic responses to optimize plant growth and development. PhyB exists in two photoconvertible forms: a red light-absorbing (Pr) and a far-red light-absorbing (Pfr) form. Therefore, to understand the mechanism of phototransformation, the structural characterization of full-length phyB in these two forms is necessary. Here, we report the molecular structure of Arabidopsis thaliana phyB in Pr form and the molecular properties of the Pfr form determined by small-angle X-ray scattering coupled with size-exclusion chromatography. In solution, the Pr form associated as a dimer with a radius of gyration of 50 Å. The molecular shape was a crossed shape, in which the orientation of the photosensory modules differed from that in the crystal structure of dimeric photosensory module. PhyB exhibited structural reversibility in the Pfr-to-Pr phototransformation and thermal reversion from Pfr to Pr in the dark. In addition, Pfr only exhibited nonspecific association, which distinguished molecular properties of Pfr form from those of the inactive Pr form.

Original languageEnglish
Pages (from-to)1612-1625
Number of pages14
JournalFEBS Journal
Issue number8
Publication statusPublished - 2020 Apr 1


  • light-induced changes
  • molecular shape
  • phytochrome B
  • size-exclusion chromatography
  • small-angle X-ray scattering

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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