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Modo de unión y potencial de activación transcripcional de los ligandos de alta afinidad para el dominio KIX de CBP
Heather M Volkman1, Stacey E Rutledge, Alanna Schepartz
1Department of Chemistry, Yale University, New Haven, CT 06520-8107, USA.
Journal of the American Chemical Society
|March 31, 2005
Resumen
Los nuevos ligandos, PPKID4 (((P) y PPKID6 (((U), imitan el dominio de activación de CREB KID que se une a CBP KIX. PPKID4 (((P) se une de manera similar a KID (((P), mientras que PPKID6 (((U) se une a una región distinta, lo que afecta la potencia de activación transcripcional.
Área de la Ciencia:
- Biología Molecular Biología Molecular
- La bioquímica es la bioquímica.
- Biología Estructural Biología estructural.
Sus antecedentes:
- El dominio de activación CREB KID (KID(P)) interactúa con el dominio KIX de CBP para regular la transcripción.
- Los ligandos diseñados PPKID4 (((P) (4 (((P)) y PPKID6 (((U) (6 (((U)) presentan el epítopo alfa-helical KID (((P) en un andamio de pliegue pancreático.
- Estos ligandos se unen a CBP KIX (KIX) y compiten con KID (P).
Objetivo del estudio:
- Para investigar el modo de unión y la orientación de 4(P) y 6(U) a CBP KIX.
- Para evaluar el potencial de activación transcripcional de estos ligandos diseñados.
- Comprender la relación entre la afinidad de unión y la actividad transcripcional.
Principales métodos:
- Experimentos de unión al equilibrio utilizando variantes KIX y ligandos 4(P) modificados.
- Análisis de los modos de unión de ligandos y las implicaciones estructurales.
- Ensayos de activación de la transcripción en células HEK293 utilizando proteínas de fusión de dominio de unión al ADN GAL4.
Principales resultados:
- 4(P) se une a KIX imitando la unión de KID(P), mientras que 6(U) se une a una región superpuesta pero distinta.
- 4(P) adopta una estructura de pliegue pancreático después de la unión de KIX.
- 4 (((P) es un potente activador de la transcripción dependiente de p300 / CBP, mientras que 6 (((U) es menos potente a pesar de una afinidad de unión similar.
Conclusiones:
- El modo de unión y la orientación de los ligandos a KIX influyen significativamente en la activación transcripcional.
- Si bien la afinidad de unión es crucial, no es el único determinante de la salida transcripcional dependiente de KIX.
- Los ligandos diseñados proporcionan información sobre las interacciones proteína-proteína y los mecanismos de regulación transcripcional.
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