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Protein Film Infrared Electrochemistry Demonstrated for Study of H2 Oxidation by a [NiFe] Hydrogenase
Published on: December 4, 2017
Síntesis, determinación de la estructura y caracterización espectroscópica / computacional de una serie de complejos
Adam T Fiedler1, Heather L Halfen, Jason A Halfen
1University of Wisconsin-Eau Claire, Department of Chemistry, 105 Garfield Avenue, Eau Claire, WI 54702, USA.
Journal of the American Chemical Society
|February 11, 2005
Resumen
Los investigadores desarrollaron complejos sintéticos de hierro-tiolato para modelar las superóxido reductasas (SOR). El Complejo 3 imita de cerca la estructura electrónica del sitio activo SOR reducido, revelando conocimientos sobre la unión hierro-azufre.
Área de la Ciencia:
- Química bioorgánica Química bioorgánica.
- Mimicría del sitio activo de la enzima.
- Coordinación Química de la Coordinación
Sus antecedentes:
- Las reductasas de superóxido (SOR) son enzimas que desintoxican el superóxido en los organismos anaerobios.
- El sitio activo de los SOR reducidos contiene un centro Fe(II) cuadrado-piramidal coordinado por ligandos de nitrógeno y azufre.
- Comprender la estructura electrónica de estos sitios activos es crucial para la función de las enzimas.
Objetivo del estudio:
- Síntesis y caracterización de nuevos complejos Fe(II) -tiolato como modelos estructurales y electrónicos del sitio activo SOR reducido.
- Para investigar la naturaleza de la unión Fe (II) -S en complejos con ligadura de tiolato axial.
- Para dilucidar la estructura electrónica y las propiedades espectrales de estos complejos modelo y compararlos con la enzima nativa.
Principales métodos:
- Enfoques combinados sintéticos, espectroscópicos (UV-Vis, MCD, VTVH-MCD) y computacionales (DFT, INDO/S-CI).Enfoques en los que se ha utilizado una combinación de tecnología y tecnología.
- Cristalografía de rayos X para la determinación estructural de complejos de Fe (II) -tiolato.
- Caracterización electroquímica de los complejos sintetizados.
Principales resultados:
- Síntesis y caracterización de los complejos 2 y 3 de Fe ((II) -tiolato, con un conjunto de donantes N ((4) S y geometrías intermedias entre piramidal cuadrado y trigonal bipyramidal.
- El detallado análisis espectroscópico y computacional proporcionó información sobre las transiciones y enlaces de transferencia de carga Fe (II) -S.
- El Complejo 3 exhibió un espectro de absorción muy similar al de la enzima SOR reducida (SOR rojo), lo que indica una imitación precisa de la estructura electrónica del sitio activo, en particular las interacciones covalentes Fe-S pi- y sigma.
Conclusiones:
- El Complejo 3, con su tiolato de alquilo atado, modela efectivamente la estructura electrónica del sitio activo SOR (rojo), incluida la orientación del residuo de cisteína.
- El estudio proporciona información significativa sobre la naturaleza del enlace Fe (II) -S en sistemas biológicamente relevantes.
- Los hallazgos tienen implicaciones para la comprensión de la estructura electrónica y la reactividad de las superóxido reductasas.
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