Structural basis of ultraviolet-B perception by UVR8.
Nature
; 484(7393): 214-9, 2012 Feb 29.
Article
em En
| MEDLINE
| ID: mdl-22388820
ABSTRACT
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 ß-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.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Raios Ultravioleta
/
Proteínas Cromossômicas não Histona
/
Arabidopsis
/
Proteínas de Arabidopsis
/
Transdução de Sinal Luminoso
Idioma:
En
Ano de publicação:
2012
Tipo de documento:
Article