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Conocimientos estructurales sobre la activación NEDD8 de las ligasas cullin-RING: control conformacional de la

David M Duda¹, Laura A Borg, Daniel C Scott

¹Howard Hughes Medical Institute, St Jude Children's Research Hospital, Memphis, TN 38105, USA.

|September 23, 2008

Resumen

La actividad de las ligasas Cullin-RING (CRL) está controlada por la modificación NEDD8. Este cambio estructural desfavorece las formas inactivas, promoviendo la poliubiquitinación y mejorando la función de los LCR.

Área de la Ciencia:

La bioquímica es la bioquímica.
Biología Estructural Biología estructural.
Biología Molecular Biología Molecular

Sus antecedentes:

Las ligasas Cullin-RING (CRL) son una clase importante de enzimas ubiquitina E3.
La modificación NEDD8 de los LCR activa su actividad de ubiquitinación e inhibe la unión a CAND1.

Objetivo del estudio:

Investigar los cambios estructurales y conformacionales en los LCR tras la modificación de la NEDD8.
Comprender cómo estos cambios afectan la actividad de los LCR y la unión al inhibidor.

Principales métodos:

Cristalografía de rayos X de NEDD8-modificado Cul5(ctd) -Rbx1.1.
Dispersión de rayos X de ángulo pequeño (SAXS) de NEDD8-modificado Cul1(ctd) -Rbx1.1.
Pruebas bioquímicas para evaluar la actividad de ubiquitinación.

Principales resultados:

La modificación de la NEDD8 induce reordenamientos conformacionales significativos en los LCR.
Los subdominios cullin WHB y Rbx1 RING se reorientan, eliminando el sitio de enlace CAND1.
La maleabilidad estructural es crucial tanto para la NEDD8ilación como para la subsiguiente ubiquitinación.

Conclusiones:

La ligadura NEDD8 desplaza los LCR de conformaciones inactivas y cerradas a formas dinámicas y abiertas.
Este control conformacional por NEDD8 promueve la poliubiquitinación y mejora la actividad de los LCR.
Los hallazgos revelan un mecanismo de regulación conformacional en la función de los LCR.

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