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Published on: December 4, 2017
Estudios espectroscópicos y computacionales de la Ni superóxido dismutasa: contribuciones de la estructura
Adam T Fiedler1, Peter A Bryngelson, Michael J Maroney
1University of Wisconsin-Madison, Department of Chemistry, Madison, Wisconsin 53706, USA.
Journal of the American Chemical Society
|April 14, 2005
Resumen
Las enzimas superóxido dismutasa (NiSOD) que contienen níquel desintoxican los radicales superóxido dañinos. Este estudio revela una fuerte unión Ni-S en NiSOD, crucial para su función y el ajuste del potencial redox en organismos aeróbicos.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Química bioorgánica Química bioorgánica.
- La espectroscopia es una técnica de espectroscopia.
Sus antecedentes:
- La superóxido dismutasa que contiene níquel (NiSOD) es una metalloenzima descubierta recientemente.
- El NiSOD desintoxica los radicales superóxido en los organismos aeróbicos, jugando un papel vital en la defensa celular.
Objetivo del estudio:
- Para investigar la estructura electrónica del sitio activo de NiSOD en sus estados oxidados (NiSOD(ox)) y reducidos (NiSOD(rojo)).
- Para dilucidar las interacciones de enlace y su influencia en la función de NiSOD y el potencial redox.
Principales métodos:
- Utilizó una combinación de técnicas espectroscópicas (incluida la espectroscopia Raman de resonancia).
- Métodos computacionales empleados para cálculos de estructura electrónica.
- Resultados computados validados contra datos experimentales.
Principales resultados:
- Se identificaron fuertes interacciones de enlace sigma entre el Ni y los ligandos S/N ecuatoriales en NiSOD (((ox), que se correlacionan con las transiciones de transferencia de carga cerca del UV.
- Se observaron modos de estiramiento de Ni-S ((Cys) a 349 y 365 cm ((-1) en NiSOD ((ox) a través de la espectroscopia Raman de resonancia.
- Se caracteriza por una alta covalencia de enlaces metal-ligando y las interacciones Ni-S/N pi en NiSOD (rojo), cruciales para ajustar el potencial redox Ni (-2+).
Conclusiones:
- La estructura electrónica del NiSOD es clave para su función de desintoxicación de superóxido.
- Un ligando aniónico N-donante es esencial para la oxidación a base de metal del sitio activo.
- La comparación con los complejos sintéticos pone de relieve la unión única Ni-S(Cys) en NiSOD.
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