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Setup of Capillary Electrophoresis-Inductively Coupled Plasma Mass Spectrometry CE-ICP-MS for Quantification of Iron Redox Species FeII, FeIII
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La inserción de hierro en el sitio de ensamblaje de la proteína de andamio ISCU es un proceso conservado que inicia
Batoul Srour1, Sylvain Gervason1, Maren Hellen Hoock2
1Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France.
Journal of the American Chemical Society
|September 19, 2022
Resumen
La biosíntesis de clúster de hierro-azufre comienza con la inserción de hierro en la proteína del andamio ISCU
Área de la Ciencia:
- La bioquímica
- Biología molecular
- Biología estructural
Sus antecedentes:
- Los grupos de hierro-azufre (Fe-S) son grupos protésicos vitales en las proteínas.
- Su biosíntesis involucra proteínas de andamio como ISCU y maquinaria conservada.
- El mecanismo inicial de inserción de hierro en el ISCU sigue sin estar claro.
Objetivo del estudio:
- Para aclarar el mecanismo de la inserción inicial de hierro ferroso en la proteína del andamio ISCU.
- Determinar el sitio de unión y la coordinación del hierro durante la biosíntesis del racimo de Fe-S.
- Investigar el papel de los aminoácidos conservados en la unión del hierro y la adquisición de azufre en las ISCU.
Principales métodos:
- Cromatografía por exclusión de tamaño (SEC)
- Espectroscopia de dicroísmo circular (CD)
- Espectroscopia de Mössbauer
- Mutagénesis dirigida al sitio
- Espectroscopia de resonancia magnética nuclear (RMN)
- Espectroscopia de absorción de rayos X
- Espectroscopia de resonancia paramagnética de electrones (EPR)
Principales resultados:
- El hierro se une al sitio de ensamblaje de ISCU a través de una o dos cisteínas (formas 1-Cys y 2-Cys).
- La forma 2-Cys predomina a pH 8,0 y se correlaciona con la actividad de ensamblaje de Fe-S.
- El hierro está coordinado por Cys35, Asp37, Cys61 y His103 en una geometría tetraédrica en la forma 2-Cys.
- Cys104 está posicionado para la transferencia de azufre, particularmente cuando His103 está ausente.
Conclusiones:
- El inicio de la biosíntesis del grupo Fe-S implica la inserción de hierro ferroso en el sitio de ensamblaje de ISCU.
- Se establece un mecanismo conservado de unión y coordinación del hierro por el ISCU.
- Estos hallazgos proporcionan información estructural sobre el proceso de ensamblaje del clúster de Fe-S.
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