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Reacciones pericíclicas catalizadas por enzimas dependientes de SAM en la biosíntesis de productos naturales
Masao Ohashi1,2, Fang Liu3, Yang Hai1
1Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, Los Angeles, California, USA.
Nature
|September 14, 2017
Resumen
Una enzima recientemente descubierta, LepI, cataliza reacciones pericíclicas complejas utilizando S-adenosil-l-metionina (SAM). Esta enzima facilita la síntesis estereoselectiva de productos naturales, revelando nuevas vías enzimáticas en la biosíntesis.
Área de la Ciencia:
- La bioquímica
- Química orgánica
- Síntesis de productos naturales
Sus antecedentes:
- Las reacciones pericíclicas son herramientas poderosas para crear enlaces carbono-carbono con alta selectividad.
- La catálisis enzimática de reacciones pericíclicas es rara, con solo tres ejemplos conocidos anteriormente.
- Los productos naturales complejos a menudo presentan estructuras construidas utilizando estas reacciones.
Objetivo del estudio:
- Identificar y caracterizar nuevas enzimas involucradas en la biosíntesis de productos naturales.
- Para aclarar el mecanismo de las reacciones pericíclicas catalizadas por enzimas.
- Para explorar el papel de la S-adenosil-l-metionina (SAM) en la catálisis enzimática.
Principales métodos:
- Ensayos enzimáticos con la enzima LepI purificada.
- Caracterización in vitro de la actividad catalítica.
- Estudios computacionales (por ejemplo, teoría funcional de la densidad) para modelar vías de reacción.
- Análisis de la estructura de la leporina del producto natural de hongos.
Principales resultados:
- Se identificó LepI, una enzima dependiente de la S-adenosil-l-metionina (SAM).
- LepI cataliza la deshidratación estereoselectiva seguida de tres transformaciones pericíclicas: el reordenamiento intramolecular Diels-Alder, el hetero-Diels-Alder y el retro-Claisen.
- Estas reacciones forman el núcleo de dihidropirano del producto natural fúngico leporina.
- LepI utiliza SAM como un cofactor para regular las vías biosintéticas bifurcadas.
Conclusiones:
- LepI representa una nueva enzima capaz de catalizar múltiples y complejas reacciones pericíclicas.
- El descubrimiento amplía el repertorio conocido de transformaciones pericíclicas enzimáticas.
- SAM juega un papel versátil en la catálisis enzimática, potencialmente en otras vías no descubiertas.
- Este trabajo proporciona información sobre la biosíntesis de la leporina y los productos naturales de hongos.
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