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Interacción molecular de una máquina de ensamblaje para la reductasa de óxido nitroso
Christoph Müller1, Lin Zhang1, Sara Zipfel1
1Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany.
Nature
|July 27, 2022
Resumen
Los investigadores descubrieron cómo la reductasa de óxido nitroso (N2OR) ensambla su complejo sitio activo de cobre. El complejo NosDFY actúa como un transductor de energía, facilitando la transferencia de cobre de NosL a N2OR para la reducción de N2O.
Área de la Ciencia:
- La bioquímica
- Biología estructural
- Ciencias del medio ambiente
Sus antecedentes:
- El óxido nitroso (N2O) es un potente gas de efecto invernadero y una sustancia que agota el ozono.
- La desnitrificación bacteriana reduce el N2O a N2 a través de la reductasa de óxido nitroso dependiente del cobre (N2OR).
- El ensamblaje único del sitio activo [4Cu:2S] (CuZ) del N2OR requiere NosDFY y NosL.
Objetivo del estudio:
- Para aclarar el mecanismo de ensamblaje del sitio activo de CuZ en N2OR.
- Determinar la base estructural para el tráfico de cobre y la formación de sitios activos de N2OR.
Principales métodos:
- Para determinar las estructuras se utilizó la criomicroscopia electrónica (Cryo-EM).
- Se resolvieron las estructuras de los complejos de Pseudomonas stutzeri NosDFY, NosL y N2OR.
Principales resultados:
- NosDFY se une al cobre (Cu+) a través de su subunidad NosD.
- NosDFY interactúa con NosL en estado libre de nucleótidos y con N2OR al unirse al ATP.
- La unión de ATP desencadena un cambio conformacional en NosD, lo que permite el cambio de pareja para la entrega de cobre.
Conclusiones:
- NosDFY funciona como un transductor de energía mecánica, no como un transportador.
- Se revela una ruta secuencial para el tráfico de cobre y el montaje del sitio CuZ.
- Este mecanismo vincula la hidrólisis del ATP en el citoplasma con la transferencia de cobre en el periplasma para la reducción de N2O.
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