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Las glutaredoxinas de monotiol pueden unirse a grupos [Fe3S4]+ y [Fe4S4]2+ lineales además de grupos [Fe2S2]2+:
Bo Zhang1, Sibali Bandyopadhyay, Priyanka Shakamuri
1Department of Chemistry and Center for Metalloenzyme Studies, University of Georgia , Athens, Georgia 30602, United States.
Journal of the American Chemical Society
|September 17, 2013
Resumen
La glutaredoxina mitocondrial 5 (Grx5) de Saccharomyces cerevisiae contiene predominantemente un grupo lineal [Fe3S4], no sólo [Fe2S2], como se pensaba anteriormente. Este hallazgo tiene un impacto en la comprensión del tráfico de clúster de hierro-azufre y la maduración de proteínas.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Química bioorgánica Química bioorgánica.
- Biología Molecular Biología Molecular
Sus antecedentes:
- La glutaredoxina mitocondrial de Saccharomyces cerevisiae 5 (Grx5) es una glutaredoxina monotiol clave involucrada en el tráfico de clúster de hierro y azufre.
- La secuencia del sitio activo del CGFS se conserva en las glutaredoxinas de monotiol, lo que sugiere una función común en el manejo de grupos de hierro-azufre.
- Estudios previos a menudo interpretaron el contenido de clúster de hierro-azufre en el monotiol Grxs como [Fe2S2] ((2+) clúster.
Objetivo del estudio:
- Para caracterizar la composición de los racimos de hierro y azufre de la recombinación de Saccharomyces cerevisiae Grx5.5.
- Investigar las propiedades estructurales y electrónicas de los grupos de hierro-azufre unidos a Grx5.5.
- Para aclarar el papel de Grx5 en el tráfico de clúster de hierro-azufre y la maduración de proteínas.
Principales métodos:
- Purificación de S. cerevisiae Grx5 recombinante en condiciones aeróbicas y anaeróbicas.
- Caracterización espectroscópica que incluye la absorción UV / CD / MCD, EPR, Mössbauer y la espectroscopia Raman de resonancia.
- Estudios mutacionales y analíticos para evaluar la ligadura de clúster.
Principales resultados:
- El Grx5 recombinante contiene predominantemente un grupo lineal [Fe3S4](+) cuando se purifica aeróbicamente o se reconstituye anaeróbicamente con glutatión.
- Los datos espectroscópicos revelan un racimo rómbico S = 5/2 lineal [Fe3S4](+) similar a los análogos sintéticos y a la aconitasa púrpura.
- En ausencia de glutatión, Grx5 forma un dímero con un grupo [Fe4S4](2+), capaz de la activación in vitro de la apoaconitasa.
Conclusiones:
- El contenido de clúster de hierro-azufre en el monotiol Grxs, incluido Grx5, ha sido en gran medida mal interpretado, siendo predominantes los clústers [Fe3S4](+) lineales.
- Grx5 juega un papel en la eliminación y el reciclaje de grupos lineales [Fe3S4](+) bajo estrés oxidativo y en la maduración de proteínas que contienen [Fe4S4](2+).
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