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Elucidando el mecanismo de formación de doble enlace cis en la biosíntesis de epothilona
Li Tang1, Shannon Ward, Loleta Chung
1Kosan Biosciences, Inc., 3832 Bay Center Place, Hayward, California 94545, USA. tang@kosan.com
Journal of the American Chemical Society
|January 8, 2004
Resumen
El complejo enzimático de la policetida sintasa (PKS) produce epotilonas D y C. El dominio de la deshidratasa 5 (DH5) es esencial para crear el enlace doble 12,13-cis- en estos compuestos.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Biología Molecular Biología Molecular
- Síntesis de Productos Naturales.
Sus antecedentes:
- Las epotilonas son compuestos macrocíclicos aislados de la planta Sorangium cellulosum.
- Son sintetizados por un complejo enzimático modular de policetida sintasa (PKS).
- Las epotilonas D y C son penúltimos intermedios con un doble enlace 12,13-cis.
Objetivo del estudio:
- Para investigar el mecanismo de la formación de un doble enlace 12,13-cis-doble en la biosíntesis de epothilone.
- Para identificar los dominios específicos de la enzima responsables de la generación del enlace doble 12,13-cis.
- Para aclarar el papel del dominio de la deshidratasa (DH) en el módulo 5 (DH5) en la síntesis de epothilona.
Principales métodos:
- Manipulación genética del clúster de genes PKS en el cellulosum de Sorangium.
- Análisis de los intermediarios de epothilona producidos por cepas modificadas.
- Caracterización bioquímica de los dominios enzimáticos y sus actividades.
Principales resultados:
- El módulo 4 del PKS carece de un dominio de deshidratasa, pero está involucrado en la formación del enlace doble 12,13.
- La inactivación del dominio DH en el módulo 5 (DH5) condujo a la producción de 10,11-dehidro-13-hydroxyepothilone D.
- Esto confirma que se requiere DH5 para el paso 12,13 de deshidratación.
Conclusiones:
- El dominio 5 de la deshidratasa (DH5) juega un papel crucial en la formación del doble enlace 12,13-cis-doble en las epotilonas.
- Un modelo mecanicista que involucra el salto de dominio y la tartamudez modular explica la actividad iterativa de DH5.
- La comprensión de este mecanismo proporciona información sobre la biosíntesis de productos naturales complejos.
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