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Assessment of Selective mRNA Translation in Mammalian Cells by Polysome Profiling
Published on: October 28, 2014
Cómo los factores de hibernación RMF, HPF y YfiA desactivan la síntesis de proteínas
Yury S Polikanov1, Gregor M Blaha, Thomas A Steitz
1Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520-8114, USA.
Science (New York, N.Y.)
|May 19, 2012
Resumen
Las bacterias detienen la producción de proteínas en fase estacionaria al inactivar los ribosomas. Este estudio revela cómo el factor de modulación del ribosoma (RMF) y el factor promotor de la hibernación (HPF) promueven la formación de dímeros 100S, mientras que YfiA forma monómeros 70S inactivos.
Área de la Ciencia:
- Fisiología bacteriana fisiología bacteriana.
- Biología Estructural Biología estructural.
- Biología Molecular Biología Molecular
Sus antecedentes:
- La transición de las eubacterias a la fase estacionaria mediante la inactivación de los ribosomas en dímeros 100S o monómeros 70S.
- La inactivación del ribosoma en Escherichia coli involucra el factor de modulación del ribosoma (RMF), el factor promotor de la hibernación (HPF) o la proteína YfiA.
- Comprender estos mecanismos es crucial para la supervivencia bacteriana y la respuesta al estrés.
Objetivo del estudio:
- Para aclarar la base estructural de la inactivación del ribosoma por factores de fase estacionaria en las Eubacteria.
- Para determinar las estructuras cristalinas de alta resolución del ribosoma Thermus thermophilus 70S complejo con RMF, HPF y YfiA.
- Investigar cómo estos factores impiden la traducción y promueven la dimerización del ribosoma.
Principales métodos:
- Cristalografía de alta resolución de alta resolución.
- Análisis estructural de los complejos de ribosomas de Thermus thermophilus 70S.
- Análisis comparativo del sitio de unión.
Principales resultados:
- El sitio de unión de RMF en el ribosoma 70S se superpone con la secuencia de ARNm Shine-Dalgarno, inhibiendo la interacción entre ARNm y ARNr.
- HPF y YfiA se unen a sitios superpuestos que involucran mRNA, tRNA y factores de iniciación, impidiendo la iniciación de la traducción.
- La unión de RMF y HPF induce un cambio de conformación en el dominio de la cabeza 30S, promoviendo la formación de dímeros 100S, un mecanismo no observado con YfiA.
Conclusiones:
- RMF y HPF promueven la dimerización del ribosoma 100S a través de distintas interacciones estructurales y cambios conformacionales.
- YfiA inactiva los ribosomas como monómeros 70S al prevenir el inicio de la traducción sin inducir la dimerización.
- Estos hallazgos proporcionan información estructural crítica sobre la regulación del ribosoma bacteriano durante la fase estacionaria.
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