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Hidroxilación enzimática de enlaces alifáticos C-H por un cofactor Mn/Fe

Magan M Powell¹, Guodong Rao², R David Britt²

¹Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States.

Journal of the American Chemical Society

|July 20, 2023

Resumen

Este estudio revela que el manganeso, previamente desconocido para la activación del enlace C-H, es esencial para que la enzima AibH1H2 funcione fuertes enlaces alifáticos C-H. Este descubrimiento amplía las funciones conocidas de los cofactores de manganeso y hierro en las reacciones de oxidación biológica.

Área de la Ciencia:

La bioquímica
Química bioorgánica
Enzimología

Sus antecedentes:

La oxidación de enlaces C-H biológicos generalmente involucra cofactores de hemo, hierro no hemo o cobre.
Los cofactores de manganeso son conocidos por provocar oxidaciones como la división del agua, pero no generalmente por la activación de C-H.

Objetivo del estudio:

Investigar las necesidades de cofactor de la hidroxilasa del ácido 2-aminoisobutérico (AibH1H2) de Rhodococcus wratislaviensis.
Explorar el mecanismo catalítico y la estructura del sitio activo de AibH1H2 para la funcionalización del enlace C-H.

Principales métodos:

Estudios estructurales y espectroscópicos de la enzima AibH1H2.
Análisis bioinformático de proteínas relacionadas en los microorganismos.

Principales resultados:

AibH1H2 requiere manganeso para activar un fuerte enlace alifático C-H (BDE = 100 kcal/mol).
La enzima presenta un sitio activo heterobimetálico manganeso-hierro redox crucial para la activación de O2 y la unión al sustrato.
El cofactor AibH1H2 utiliza un pliegue proteico único distinto de otras oxigenasas bimetálicas.

Conclusiones:

Este trabajo expande la reactividad conocida de los cofactores biológicos de manganeso y hierro más allá de la transferencia de electrones y la oxidación de proteínas.
Los hallazgos sugieren que muchas monooxigenasas no caracterizadas pueden utilizar el manganeso para procesos bioquímicos oxidativos.
El descubrimiento destaca un papel novedoso para el manganeso en la catalización de reacciones de funcionalización de enlaces C-H.

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