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Updated: May 16, 2025

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Naturaleza del Intermedio Peróxido Biferrico Reactivo P' en las Arylamine Oxygenases y Enzimas de Fe Binucleares

Lars H Böttger¹, Dory E DeWeese¹, Shyam R Iyer¹

¹Department of Chemistry, Stanford University, Stanford, California 94305, United States.

Journal of the American Chemical Society

|April 1, 2025

Resumen

Las enzimas binucleares de hierro no hemo activan el O2 a través de un intermediario peroxi.

Área de la Ciencia:

La bioquímica
Química bioorgánica
Enzimología

Sus antecedentes:

Las enzimas de hierro no hemo binucleares son cruciales para la activación del oxígeno en varias transformaciones biológicas.
La activación con oxígeno implica un intermediario biferrico peroxi (P), que puede procesarse más a fondo.
Comprender los intermediarios como P' es clave para dilucidar los mecanismos de las enzimas.

Objetivo del estudio:

Definir las características estructurales del intermedio P' en las N-oxigenasas CmlI y AurF.
Investigar el papel de la protonación y los ligandos puentes en las vías de activación del oxígeno.

Principales métodos:

Espectroscopia vibratoria de resonancia nuclear (NRVS) combinada con cálculos de la teoría funcional de la densidad (DFT).
Espectroscopia de dicroísmo circular magnético (MCD) con temperatura variable y campo variable (VTVH).
Cálculos de las coordenadas de reacción.

Principales resultados:

El intermedio P' presenta un sitio biferrico μ-1,2-hidroxoperoxo con un puente de hidróxido adicional.
La protonación del grupo peroxo facilita la escisión reductora a través de la transferencia de un solo electrón (SET).
El puente de hidróxido no impide SET, y está ausente en el precursor biferroso.

Conclusiones:

La estructura intermedia P' se elucida como un complejo biferrico μ-1,2-hidroxoperoxo con un segundo puente de hidróxido.
La protonación del ligando peroxo es crítica para activar la escisión reductiva.
Una molécula de agua probablemente forma el puente de hidróxido durante la activación de oxígeno por el sitio biferro.

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