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Reducción del ciclopropeno fluorado por la nitrogenasa
Feng Ni1, Chi Chung Lee, Candy S Hwang
1Department of Chemistry, University of Southern California, Los Angeles, California 90089-0744, United States.
Journal of the American Chemical Society
|July 10, 2013
Resumen
La nitrogenasa (N2asa) reduce el 3,3-difluorociclopropeno (DFCP), rompiendo los enlaces carbono-fluoro para formar propeno y 2-fluoropropeno. Esto demuestra la N2asa.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Enzimología Enzimología.
- Química organometálica Química orgánica de los metales.
Sus antecedentes:
- La nitrogenasa (N2asa) es una enzima compleja esencial para la fijación biológica del nitrógeno.
- Investigar el alcance del sustrato de la N2asa revela su versatilidad catalítica.
- Los compuestos halogenados son típicamente recalcitrantes a la reducción biológica.
Objetivo del estudio:
- Para investigar la reducción de 3,3-difluorociclopropeno (DFCP), el primer sustrato conocido que contiene halógenos, por N2ase.
- Para aclarar el mecanismo y los productos de la reducción de DFCP.
- Para explorar las capacidades catalíticas de la N2asa en la escisión de enlaces C-F.
Principales métodos:
- Ensayos de reducción enzimática utilizando componentes purificados de N2asa (proteínas MoFe y Fe).
- Identificación de los productos de reducción (propeno y 2-fluoropropeno) mediante el uso de la cromatografía de gases-espectrometría de masas (GC-MS) y la espectroscopia de resonancia magnética nuclear (RMN).
- Estudios de etiquetado de deuterio (d2-DFCP) para rastrear las vías de reacción y los intermediarios.
Principales resultados:
- La N2asa reduce los enlaces C-F en el DFCP, dando propeno (P1) y 2-fluoropropeno (P2).
- Ambos productos requerían ATP y un reductor exógeno (ditionita), similar a la reducción de N2.
- El etiquetado de deuterio indicó la escisión de enlaces CC y reveló restricciones geométricas en los intermediarios de reducción.
Conclusiones:
- La N2asa posee la capacidad de cortar reductivamente los enlaces carbono-fluoro.
- DFCP sirve como un nuevo sustrato, expandiendo el conocido repertorio catalítico de N2ase.
- Los hallazgos ponen de relieve el notable y único alcance de las proezas enzimáticas de la N2asa.
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