Photoadduct Formation from the FMN Singlet Excited State in the LOV2 Domain of Chlamydomonas reinhardtii Phototropin.
J Phys Chem Lett
; 7(21): 4380-4384, 2016 Nov 03.
Article
en En
| MEDLINE
| ID: mdl-27766868
ABSTRACT
The two light, oxygen, and voltage domains of phototropin are blue-light photoreceptor domains that control various functions in plants and green algae. The key step of the light-driven reaction is the formation of a photoadduct between its FMN chromophore and a conserved cysteine, where the canonical reaction proceeds through the FMN triplet state. Here, complete photoreaction mapping of CrLOV2 from Chlamydomonas reinhardtii phototropin and AsLOV2 from Avena sativa phototropin-1 was realized by ultrafast broadband spectroscopy from femtoseconds to microseconds. We demonstrate that in CrLOV2, a direct photoadduct formation channel originates from the initially excited singlet state, in addition to the canonical reaction through the triplet state. This direct photoadduct reaction is coupled by a proton or hydrogen transfer process, as indicated by a significant kinetic isotope effect of 1.4 on the fluorescence lifetime. Kinetic model analyses showed that 38% of the photoadducts are generated from the singlet excited state.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Fotoquímica
/
Chlamydomonas reinhardtii
/
Fototropinas
/
Mononucleótido de Flavina
Idioma:
En
Revista:
J Phys Chem Lett
Año:
2016
Tipo del documento:
Article
País de afiliación:
Países Bajos