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La O-metilación de la hidroxiquinona en la biosíntesis de la mitomicina
Sabine Grüschow1, Leng-Chee Chang, Yingqing Mao
1Life Sciences Institute, Department of Medicinal Chemistry, University of Michigan, Ann Arbor, MI 48109, USA.
Journal of the American Chemical Society
|April 28, 2007
Resumen
La MmcR metiltransferasa es crucial para producir las mitomicinas A y B mediante la adición de un grupo metoxí. Este paso de metilación es esencial para la biosíntesis de la mitomicina C, un fármaco clave en la quimioterapia.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Biología Molecular Biología Molecular
- Biosíntesis de Productos Naturales de Productos Naturales
Sus antecedentes:
- Las mitomicinas son agentes alquiladores de ADN activados biorreductivamente utilizados en la terapia del cáncer.
- La citotoxicidad de las mitomicinas depende de su potencial electroquímico, influenciado por los sustitutos de quinona.
- El grupo metoxico de quinona en las mitomicinas A y B es crítico para su actividad.
Objetivo del estudio:
- Investigar la biogénesis del grupo metoxico de quinona en las mitomicinas A y B.
- Determinar el papel del gen de la metiltransferasa mmcR en la producción de mitomicina.
- Aclarar la necesidad de 7-O-metilación para la biosíntesis de mitomicina C.
Principales métodos:
- Estudios de eliminación de genes: cepa de Streptomyces lavendulae modificada por ingeniería con mmcR eliminado.
- Análisis de metabolitos: extractos de cultivos analizados de cepas de tipo silvestre y mutantes.
- Ensayos enzimáticos: clonación y sobreexpresión de MmcR metiltransferasa para estudios de metilación in vitro.
Principales resultados:
- La eliminación de mmcR abolió la producción de mitomicinas A, B y C.
- Se observó acumulación de 7-demetilmitomicina A y B en la cepa mutante.
- MmcR catalizó la 7-O-metilación de las 7-hidroximitomicinas in vitro, restaurando la producción de mitomicina cuando se suministraron los precursores.
Conclusiones:
- La MmcR metiltransferasa juega un papel catalítico directo en la formación del grupo 7-metoxi de las mitomicinas A y B.
- La 7-O-metilación es un requisito previo para la biosíntesis del agente clínico mitomicina C.
- Comprender la biosíntesis de la mitomicina proporciona información sobre el desarrollo de nuevos agentes alquilantes del ADN.
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