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Design and Synthesis of a Reconfigurable DNA Accordion Rack
Published on: August 15, 2018
Enlace de nucleótidos y conmutación conformacional en el anillo hexamericano de una máquina AAA+
Benjamin M Stinson1, Andrew R Nager, Steven E Glynn
1Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Cell
|April 30, 2013
Resumen
El hexámero de proteínas ClpX requiere cambios dinámicos de conformación entre los estados de carga y descarga de nucleótidos. Esta interconversión dinámica es esencial para acoplar la hidrólisis de ATP al trabajo mecánico en el despliegue y la degradación de las proteínas.
Área de la Ciencia:
- Biología Molecular Biología Molecular
- La bioquímica es la bioquímica.
- La degradación de las proteínas.
Sus antecedentes:
- ClpX es un homohexámero de anillo AAA + que utiliza ATP para desplegar y translocar proteínas en la peptidasa ClpP para la degradación.
- Las estructuras cristalinas revelan que las subunidades de ClpX existen tanto en conformaciones con carga de nucleótidos como en conformaciones sin carga con una variabilidad significativa.
Objetivo del estudio:
- Investigar el papel de la interconversión dinámica entre las conformaciones de las subunidades de ClpX en el acoplamiento de la hidrólisis de ATP al trabajo mecánico.
- Comprender cómo los cambios alostéricos por etapas y la conmutación de subunidades facilitan la función de ClpX.
Principales métodos:
- Mutagénesis dirigida al sitio de subunidades individuales dentro de hexámeres de ClpX atados covalentemente.
- Pruebas basadas en fluorescencia para monitorear las conformaciones de las subunidades y las propiedades de unión de nucleótidos.
Principales resultados:
- La interconversión dinámica entre las conformaciones cargables y descargables es crucial para acoplar la hidrólisis de ATP al trabajo mecánico.
- La unión de ATP induce cambios alostéricos por etapas, preparando el anillo para la hidrólisis y los pasos mecánicos.
- La conmutación de la subunidad restablece la configuración del anillo cargado de nucleótidos, que es esencial para la función mecánica.
Conclusiones:
- El mecanismo funcional de ClpX se basa en la interacción dinámica entre los diferentes estados conformacionales de las subunidades.
- Esta flexibilidad conformacional permite que ClpX realice eficientemente el trabajo mecánico, incluido el despliegue y la translocación de proteínas.
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