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Combining Chemical Cross-linking and Mass Spectrometry of Intact Protein Complexes to Study the Architecture of Multi-subunit Protein Assemblies
Published on: November 28, 2017
Conocimientos moleculares sobre el ensamblaje de la cadena de la poliubiquitina: estructura cristalina del
A P VanDemark1, R M Hofmann, C Tsui
1Department of Biophysics and Biophysical Chemistry, School of Medicine, Johns Hopkins University, Baltimore, MD, USA.
Cell
|July 7, 2001
Resumen
Este estudio revela cómo los complejos de proteínas Mms2/Ubc13 ensamblan cadenas específicas de poliubiquitina ligadas a Lys63 esenciales para la reparación del ADN y las vías de señalización celular.
Área de la Ciencia:
- Biología Molecular Biología Molecular
- La bioquímica es la bioquímica.
- Biología Estructural Biología estructural.
Sus antecedentes:
- La topología de la cadena de ubiquitina dicta la señalización, pero la especificidad del ensamblaje se entiende mal.
- Las cadenas de poliubiquitina ligadas a Lys63 son señales cruciales en la reparación del ADN y la activación de la quinasa.
- Los complejos UEV/Ubc participan en el ensamblaje de estas cadenas específicas.
Objetivo del estudio:
- Para dilucidar la base molecular de la especificidad en el ensamblaje de la cadena de poliubiquitina ligada a Lys63.
- Comprender las funciones estructurales y funcionales del heterodímero Mms2/Ubc13 en la reparación del ADN.
Principales métodos:
- Cristalografía de rayos X para determinar la estructura del heterodímero Mms2/Ubc13.
- Mutagenesis dirigida al sitio para investigar la función de regiones específicas de proteínas.
- Evaluación de la sensibilidad UV para evaluar las capacidades de reparación del ADN.
Principales resultados:
- La estructura cristalina reveló el sitio activo de Ubc13 posicionado entre dos potenciales canales de unión a la ubiquitina.
- Las mutaciones que desestabilizan la interfaz heterodímero Mms2/Ubc13 llevaron a una sensibilidad UV significativa.
- Las mutaciones dirigidas dentro de los canales proporcionaron información sobre la especificidad del ensamblaje de la cadena vinculada a Lys63.
Conclusiones:
- El heterodímero Mms2/Ubc13 intacto es esencial para una eficiente reparación del ADN.
- Se propone un modelo molecular para un conjunto específico de señales de poliubiquitina ligadas a Lys63 basado en hallazgos estructurales.
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