Flavin-Radical Formation in the Light-Oxygen-Voltage-Sensing Domain of the Photozipper Blue-light Sensor Protein.
J Phys Chem B
; 122(38): 8819-8823, 2018 09 27.
Article
en En
| MEDLINE
| ID: mdl-30157376
ABSTRACT
Formation of the neutral flavin radical in the light-oxygen-voltage-sensing (LOV-sensing) domain of photozipper, based on VfAUREO1, was investigated by electron paramagnetic resonance spectroscopy. The flavin radical was observed in the presence of dithiothreitol by illumination of a LOV-domain mutant (C254S), in which a photoactive cysteine residue in close proximity to flavin was replaced with a serine. The radical did not form under low initial protein-concentration conditions (less than 20 µM). The flavin radicals accumulated with logistic time-dependent kinetics when the protein concentrations were higher than 30 µM. These results indicate that the radical is produced by concerted reactions involving protein interactions and that the radical is formed from the LOV dimer but not the LOV monomer. In contrast, logistic time dependencies were not observed for the sample adapted to the dark following radical formation by illumination, indicating that initialization of the proton pathway is essential for this fast sensing reaction.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Proteínas de Unión al ADN
/
Mononucleótido de Flavina
/
Radicales Libres
Idioma:
En
Revista:
J Phys Chem B
Asunto de la revista:
QUIMICA
Año:
2018
Tipo del documento:
Article
País de afiliación:
Japón