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Reconocimiento de ARN por péptidos derivados de Tat: interacción en el surco mayor

K M Weeks¹, D M Crothers

¹Department of Chemistry, Yale University, New Haven, Connecticut 06511.

|August 9, 1991

Resumen

La unión de alta afinidad de la proteína Tat del virus de la inmunodeficiencia humana a su objetivo de ARN requiere secuencias y geometría de bucle de bulto específicas. Esta interacción es crucial para la replicación viral, permitiendo el acceso de la proteína a la ranura principal del ARN.

Área de la Ciencia:

Biología Molecular Biología Molecular
Virología Virología.
Biología Estructural Biología estructural.

Sus antecedentes:

La replicación del virus de la inmunodeficiencia humana (VIH) depende de la unión de la proteína Tat viral a la secuencia de ARN TAR.
Los péptidos derivados de Tat interactúan con un sitio específico de ARN, incluida una protuberancia de pirimidina.

Objetivo del estudio:

Para aclarar la secuencia y los requisitos estructurales para la unión de ARN Tat-TAR de alta afinidad.
Para entender cómo la estructura del ARN facilita la interacción de las proteínas.

Principales métodos:

Análisis de la unión del péptido derivado de Tat a varias construcciones de ARN abultadas.
Prueba química (pirocarbonato de dietilo) para evaluar la accesibilidad al ARN.

Principales resultados:

La unión de alta afinidad requiere un residuo de uridina dentro de la protuberancia y dos pares de bases adyacentes específicos.
La unión específica de la secuencia requiere un bucle de protuberancia más largo que un nucleótido.
La protuberancia de ARN distorsiona la geometría de la forma A, doblando la hélice y abriendo la ranura principal para el acceso de la proteína.

Conclusiones:

Las estructuras específicas de protuberancia de ARN son críticas para el reconocimiento de proteínas Tat de alta afinidad.
Las distorsiones estructurales locales del ARN facilitan la unión a las proteínas en la ranura principal, esencial para la replicación del VIH.

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