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Ciclización del poliquetido de fenalenona catalizada por la poliquetasa fúngica y la monooxigenasa dependiente de la

Shu-Shan Gao¹, Abing Duan¹, Wei Xu¹

¹Department of Chemical and Biomolecular Engineering and ‡Department of Chemistry and Biochemistry, University of California , Los Angeles, California 90095, United States.

Journal of the American Chemical Society

|March 16, 2016

Resumen

Los investigadores descubrieron nuevas vías para sintetizar las fenalenonas, una clase de productos naturales. Identificaron enzimas clave, incluida una poliquetida sintasa y una monooxigenasa únicas, que impulsan el inusual proceso de ciclización.

Área de la Ciencia:

Biosíntesis de productos naturales
Química de las policetidas
Enzimología

Sus antecedentes:

Las fenalenonas son productos naturales con estructuras complejas y actividades biológicas.
Su estructura central se forma a través de una ciclización inusual de un precursor poliquetídeo lineal.
El mecanismo exacto de esta ciclización ha permanecido en gran medida sin resolver.

Objetivo del estudio:

Para aclarar la vía de biosíntesis y el mecanismo de ciclización inusual de las fenalenonas.
Identificar las enzimas específicas involucradas en la formación de núcleos de fenalenona.
Comprender las funciones catalíticas de estas enzimas en la ciclización de policetidos.

Principales métodos:

Análisis genómico para identificar el grupo de genes biosintéticos phn en Penicillium herquei.
Caracterización bioquímica de la poliquetida sintasa no reductora (NR-PKS) PhnA.
Ensayos enzimáticos y análisis de producto para PhnA y la monooxigenasa dependiente de FAD (FMO) PhnB.
Cálculos de la teoría funcional de la densidad (DFT) para modelar los mecanismos de reacción.

Principales resultados:

Se identificó el clúster de genes phn, y se demostró que PhnA sintetiza la columna vertebral heptaketida y la cicliza a la prefenalenona.
El dominio de la plantilla de producto (PT) de PhnA cataliza de manera única una condensación de aldol.
PhnB fue identificado como un FMO que realiza simultáneamente la hidroxilación aromática C2 y la apertura del anillo γ-pirona.
Los cálculos de DFT apoyaron un nuevo mecanismo de ciclización de fenoxido y cetona para la formación de fenalenona.

Conclusiones:

Se han descubierto nuevas rutas biosintéticas y biocatalizadores para la ciclización de la fenalenona.
El estudio revela mecanismos enzimáticos sin precedentes en la biosíntesis de policetida.
Este trabajo proporciona una base para la comprensión y la ingeniería de la producción de fenalenona.

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