Structural basis of ultraviolet-B perception by UVR8

Nature. 2012 Feb 29;484(7393):214-9. doi: 10.1038/nature10931.


The Arabidopsis thaliana protein UVR8 is a photoreceptor for ultraviolet-B. Upon ultraviolet-B irradiation, UVR8 undergoes an immediate switch from homodimer to monomer, which triggers a signalling pathway for ultraviolet protection. The mechanism by which UVR8 senses ultraviolet-B remains largely unknown. Here we report the crystal structure of UVR8 at 1.8 Å resolution, revealing a symmetric homodimer of seven-bladed β-propeller that is devoid of any external cofactor as the chromophore. Arginine residues that stabilize the homodimeric interface, principally Arg 286 and Arg 338, make elaborate intramolecular cation-π interactions with surrounding tryptophan amino acids. Two of these tryptophans, Trp 285 and Trp 233, collectively serve as the ultraviolet-B chromophore. Our structural and biochemical analyses identify the molecular mechanism for UVR8-mediated ultraviolet-B perception, in which ultraviolet-B radiation results in destabilization of the intramolecular cation-π interactions, causing disruption of the critical intermolecular hydrogen bonds mediated by Arg 286 and Arg 338 and subsequent dissociation of the UVR8 homodimer.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / chemistry*
  • Arabidopsis Proteins / chemistry*
  • Arabidopsis Proteins / radiation effects*
  • Cations / chemistry
  • Chromosomal Proteins, Non-Histone / chemistry*
  • Chromosomal Proteins, Non-Histone / radiation effects*
  • Crystallography, X-Ray
  • Light Signal Transduction / radiation effects*
  • Models, Molecular
  • Protein Conformation / radiation effects
  • Protein Multimerization / radiation effects
  • Tryptophan / chemistry
  • Tryptophan / metabolism
  • Ultraviolet Rays*


  • Arabidopsis Proteins
  • Cations
  • Chromosomal Proteins, Non-Histone
  • Uvr8 protein, Arabidopsis
  • Tryptophan

Associated data

  • PDB/4DNU
  • PDB/4DNV
  • PDB/4DNW