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Bases estructurales de la percepción de la hormona esteroide por la receptor kinasa BRI1
Michael Hothorn1, Youssef Belkhadir, Marlene Dreux
1Plant Biology Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, California 92037, USA.
Nature
|June 14, 2011
Resumen
Los receptores de esteroides vegetales como el BRASSINOSTEROID INSENSITIVE 1 (BRI1) tienen una estructura única para la unión con las hormonas. Esta investigación revela la estructura del dominio de unión de ligandos BRI1, crucial para el crecimiento de las plantas y la señalización de la inmunidad.
Área de la Ciencia:
- Biología vegetal Biología vegetal
- Biología molecular y estructural Biología molecular y estructural
- La bioquímica es la bioquímica.
Sus antecedentes:
- Los esteroides polihidroxilados regulan el tamaño y la forma del organismo.
- En los animales, los receptores intracelulares se unen a los esteroides, mientras que las plantas utilizan las cinasas receptoras ligadas a la membrana como BRASSINOSTEROID INSENSITIVE 1 (BRI1).
Objetivo del estudio:
- Para determinar la estructura del dominio de unión de ligando BRI1 de la Arabidopsis thaliana.
- Comprender las bases moleculares de la percepción de brassinolides por el BRI1.1.
Principales métodos:
- Difracción de rayos X a una resolución de 2.5 Å.
- Análisis estructural del dominio de unión a los ligandos BRI1.
Principales resultados:
- El dominio de unión de ligandos BRI1 presenta una súper hélice de 25 repeticiones ricas en leucina (LRR).
- Un dominio único de isla de 70 aminoácidos forma un bolsillo para la unión de brassinolides.
- Las mutaciones conocidas se correlacionan con el sitio de unión de la hormona.
Conclusiones:
- La unión de esteroides a BRI1 probablemente crea un sitio de acoplamiento de co-receptor para la activación del receptor.
- Esta estructura proporciona información sobre el mecanismo de activación de la hormona vegetal, el desarrollo y los receptores de señalización de inmunidad.
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