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Apertura y cierre de la pinza de ARN polimerasa bacteriana

Anirban Chakraborty¹, Dongye Wang, Yon W Ebright

¹Howard Hughes Medical Institute, Waksman Institute, and Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854, USA.

Science (New York, N.Y.)

|August 4, 2012

Resumen

La pinza de ARN polimerasa bacteriana (RNAP) se abre para la carga de ADN y se cierra para la transcripción estable. Este cierre de la abrazadera es crucial para la iniciación de la transcripción y la estabilidad y la procesividad del complejo de alargamiento.

Área de la Ciencia:

Biología molecular La biología molecular.
La bioquímica es la bioquímica.
Biología estructural Biología estructural.

Sus antecedentes:

La ARN polimerasa bacteriana (RNAP) es esencial para la expresión génica.
Comprender los cambios conformacionales de la RNAP es clave para descifrar la regulación de la transcripción.

Objetivo del estudio:

Para definir la conformación de la abrazadera de la RNAP bacteriana durante la transcripción.
Aclarar el papel de la dinámica de las pinzas en la iniciación y el alargamiento de la transcripción.

Principales métodos:

Se empleó la transferencia de energía de resonancia de fluorescencia de molécula única (smFRET).
smFRET se utilizó para monitorear la conformación de la abrazadera de RNAP en tiempo real.

Principales resultados:

La pinza de RNAP está predominantemente abierta en enzimas libres e intermedios de iniciación temprana.
El cierre de la abrazadera se produce con la formación de un complejo catalíticamente competente y persiste a través del alargamiento.
Se encontraron cuatro inhibidores que impiden la apertura de la abrazadera de RNAP.

Conclusiones:

La apertura de la abrazadera facilita la carga y desenrollo del ADN.
Carga y desenrollo de ADN Cierre de la pinza del gatillo.
El cierre de la abrazadera estabiliza el inicio de la transcripción y los complejos de alargamiento, mejorando la procesividad.

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