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El plegamiento de proteínas oxidativas es impulsado por el sistema de transporte de electrones
1Department of Biology, University of Michigan, Ann Arbor 48109-1048, USA.
Cell
|July 31, 1999
Resumen
La formación de enlaces disulfuro en las células está relacionada con la producción de energía. La enzima DsbB utiliza quinonas para conectar el plegamiento de proteínas con la cadena de transporte de electrones, adaptándose a varios niveles de oxígeno.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Biología Molecular Biología Molecular
- El metabolismo celular es el metabolismo celular.
Sus antecedentes:
- La formación de enlaces disulfuro es esencial para el plegamiento y la función de las proteínas in vivo.
- Este proceso es catalizado principalmente por las proteínas DsbA y DsbB.
- Los mecanismos precisos que vinculan la formación de enlaces disulfuro con el metabolismo energético celular aún no se comprenden por completo.
Objetivo del estudio:
- Para reconstituir e investigar el sistema de plegado oxidativo in vivo utilizando componentes purificados de DsbA y DsbB.
- Para identificar las fuentes del poder oxidativo que impulsa el plegamiento de las proteínas.
- Para aclarar los vínculos directos entre la formación de enlaces disulfuro y las vías metabólicas celulares, específicamente la cadena de transporte de electrones.
Principales métodos:
- Reconstitución del sistema de formación de enlaces disulfuro utilizando proteínas DsbA y DsbB purificadas.
- Investigación de las funciones de aceptores de electrones para DsbB, incluidas las quinonas.
- Análisis de las vías de flujo de electrones a través de diferentes oxidasas (citocromo bo, citocromo bd) bajo diferentes condiciones de oxígeno.
- Examen del papel de la menaquinona en la transferencia de electrones a aceptores alternativos como el fumarato bajo condiciones anaerobias.
Principales resultados:
- La formación de enlaces disulfuro está directamente acoplada a la cadena de transporte de electrones celular.
- DsbB utiliza quinonas como aceptores de electrones, lo que permite vías de transporte de electrones flexibles.
- El sistema se adapta a las diferentes disponibilidades de oxígeno, utilizando oxidasas específicas (citocromo bo aeróbicamente, citocromo bd bajo anaerobiosis parcial) o aceptores alternativos (fumarato anaeróbicamente).
- Los componentes purificados reconstituyeron con éxito el sistema de plegado oxidativo.
Conclusiones:
- El sistema de plegamiento oxidativo, catalizado por DsbA y DsbB, está estrechamente integrado con el metabolismo energético celular.
- La flexibilidad de las vías de transporte de electrones vinculadas a DsbB pone de relieve la importancia crítica de la formación de enlaces disulfuro para la función celular.
- Comprender este acoplamiento proporciona información sobre la adaptación celular y los procesos fundamentales de maduración de las proteínas.
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