Domain organization in plant blue-light receptor phototropin2 of arabidopsis thaliana studied by small-angle x-ray scattering

Masayoshi Nakasako, Mao Oide, Yuki Takayama, Tomotaka Oroguchi, Koji Okajima

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


Phototropin2 (phot2) is a blue-light (BL) receptor protein that regulates the BL-dependent activities of plants for efficient photosynthesis. Phot2 is composed of two light-oxygen-voltage sensing domains (LOV1 and LOV2) to absorb BL, and a kinase domain. Photo-activated LOV domains, especially LOV2, play a major role in photo-dependent increase in the phosphorylation activity of the kinase domain. The atomic details of the overall structure of phot2 and the intramolecular mechanism to convert BL energy to a phosphorylation signal remain unknown. We performed structural studies on the LOV fragments LOV1, LOV2, LOV2-linker, and LOV2-kinase, and full-length phot2, using small-angle X-ray scattering (SAXS). The aim of the study was to understand structural changes under BL irradiation and discuss the molecular mechanism that enhance the phosphorylation activity under BL. SAXS is a suitable technique for visualizing molecular structures of proteins in solution at low resolution and is advantageous for monitoring their structural changes in the presence of external physical and/or chemical stimuli. Structural parameters and molecular models of the recombinant specimens were obtained from SAXS profiles in the dark, under BL irradiation, and after dark reversion. LOV1, LOV2, and LOV2-linker fragments displayed minimal structural changes. However, BL-induced rearrangements of functional domains were noted for LOV2-kinase and full-length phot2. Based on the molecular model together with the absorption measurements and biochemical assays, we discuss the intramolecular interactions and domain motions necessary for BL-enhanced phosphorylation activity of phot2.

Original languageEnglish
Article number6638
Pages (from-to)1-21
Number of pages21
JournalInternational journal of molecular sciences
Issue number18
Publication statusPublished - 2020 Sept 2


  • Photoreceptor protein
  • Phototropin2
  • Signal transduction
  • Small-angle X-ray scattering

ASJC Scopus subject areas

  • Catalysis
  • Molecular Biology
  • Spectroscopy
  • Computer Science Applications
  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry


Dive into the research topics of 'Domain organization in plant blue-light receptor phototropin2 of arabidopsis thaliana studied by small-angle x-ray scattering'. Together they form a unique fingerprint.

Cite this