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Bases estructurales para el alargamiento de la transcripción por la ARN polimerasa bacteriana

Dmitry G Vassylyev¹, Marina N Vassylyeva, Anna Perederina

¹Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Schools of Medicine and Dentistry, 402B Kaul Genetics Building, 720 20th Street South, Birmingham, Alabama 35294, USA. dmitry@uab.edu

|June 22, 2007

Resumen

La estructura del complejo de alargamiento de la polimerasa de ARN (CE) revela cómo se mueve a lo largo del ADN para sintetizar ARN. Esto proporciona información sobre los mecanismos de pausa y terminación de la ARN polimerasa.

Área de la Ciencia:

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

Sus antecedentes:

El complejo de alargamiento de la ARN polimerasa (CE) es crucial para la transcripción génica, permitiendo la síntesis rápida y procesada de ARN.
Comprender la dinámica estructural de la CE es clave para aclarar los mecanismos de transcripción y la regulación.

Objetivo del estudio:

Para determinar la estructura de alta resolución del Thermus thermophilus EC.
Para dilucidar las bases estructurales de la procesividad y regulación de la ARN polimerasa.

Principales métodos:

Se utilizó cristalografía de rayos X para obtener la estructura de la CE a una resolución de 2,5 A.

Principales resultados:

La estructura capturó un intermedio post-translocado con la plantilla de ADN accesible en el sitio activo.
La separación de la cadena de ADN se produce aguas abajo del sitio activo, limitando la unión del sustrato a uno a la vez.
El híbrido ARN/ADN y el ARN desplazado interactúan con elementos proteicos específicos, lo que sugiere mecanismos de desplazamiento de ARN.
La conformación del canal de salida del ARN proporciona información sobre la pausa y terminación dependientes de la horquilla.

Conclusiones:

La estructura de alta resolución proporciona una visión molecular detallada de la CE durante el alargamiento.
Las características estructurales explican la accesibilidad del sustrato, el desplazamiento del ARN y los posibles mecanismos de pausa / terminación.

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