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Catálisis asistida por enlace de hidrógeno: hidroxilación de paclitaxel por el CYP2C8 humano

Dongxiao Yue¹, Elvis Wang Hei Ng², Hajime Hirao¹

¹Warshel Institute for Computational Biology, School of Medicine, The Chinese University of Hong Kong, Shenzhen, Guangdong 518172, P. R. China.

Journal of the American Chemical Society

|October 23, 2024

Resumen

El metabolismo del paclitaxel por el CYP2C8 implica un mecanismo de rebote atípico. El grupo hidroxilo C7 ayuda a la catálisis, y la enzima

Área de la Ciencia:

La bioquímica
Química medicinal
Química computacional

Sus antecedentes:

El paclitaxel (PTX) es un medicamento de quimioterapia vital.
El metabolismo de PTX por CYP3A4 y CYP2C8 tiene un impacto en la eficacia.
Los mecanismos precisos del metabolismo de PTX no se comprenden completamente.

Objetivo del estudio:

Para aclarar el mecanismo del metabolismo de PTX por el CYP2C8 humano.
Investigar el papel del posicionamiento del sustrato y de los grupos funcionales específicos en la hidroxilación de PTX.

Principales métodos:

Se emplearon cálculos híbridos de mecánica cuántica / mecánica molecular (QM / MM).
Análisis de la abstracción de hidrógeno, la formación de radicales intermedios y los pasos de rebote.
Investigación de la estabilidad del estado de transición y los estados de giro.

Principales resultados:

La hidroxilación de PTX mediada por CYP2C8 sigue un mecanismo de rebote atípico.
El grupo hidroxilo C7 de PTX juega un papel catalítico en la abstracción y el rebote de hidrógeno.
La selectividad del producto se rige por el paso de rebote, favoreciendo la 6α-hidroxilación.
Se observó un estado de transición estable en el estado de sexteto de alto espín debido a las interacciones enzima- sustrato.

Conclusiones:

El estudio revela un nuevo mecanismo para el metabolismo de PTX por CYP2C8.
Las interacciones específicas de la enzima dictan la formación estereoselectiva del 6α-hidroxipaclitaxel.
La comprensión de este mecanismo podría informar estrategias para optimizar la terapia PTX.

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