Oxygen activation of apo-obelin-coelenterazine complex.
Chembiochem
; 14(6): 739-45, 2013 Apr 15.
Article
en En
| MEDLINE
| ID: mdl-23494831
ABSTRACT
Ca(2+) -regulated photoproteins use a noncovalently bound 2-hydroperoxycoelenterazine ligand to emit light in response to Ca(2+) binding. To better understand the mechanism of formation of active photoprotein from apoprotein, coelenterazine and molecular oxygen, we investigated the spectral properties of the anaerobic apo-obelin-coelenterazine complex and the kinetics of its conversion into active photoprotein after exposure to air. Our studies suggest that coelenterazine bound within the anaerobic complex might be a mixture of N7-protonated and C2(-) anionic forms, and that oxygen shifts the equilibrium in favor of the C2(-) anion as a result of peroxy anion formation. Proton removal from N7 and further protonation of peroxy anion and the resulting formation of 2-hydroperoxycoelenterazine in obelin might occur with the assistance of His175. It is proposed that this conserved His residue might play a key role both in formation of active photoprotein and in Ca(2+) -triggering of the bioluminescence reaction.
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Oxígeno
/
Pirazinas
/
Hidrozoos
/
Imidazoles
/
Proteínas Luminiscentes
Tipo de estudio:
Prognostic_studies
Límite:
Animals
Idioma:
En
Revista:
Chembiochem
Asunto de la revista:
BIOQUIMICA
Año:
2013
Tipo del documento:
Article
País de afiliación:
China