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Las estructuras cristalinas del ribosoma en complejo con los factores de liberación RF1 y RF2 unidos a un codón stop
Sabine Petry1, Ditlev E Brodersen, Frank V Murphy
1MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 2QH, United Kingdom.
Cell
|December 27, 2005
Resumen
Los investigadores visualizaron complejos ribosómicos con factores de liberación (RF1 y RF2) obligados a detener los codones. Estas estructuras cristalinas revelan cómo ocurre la terminación de la síntesis de proteínas a nivel molecular.
Área de la Ciencia:
- Biología Estructural Biología estructural.
- Biología Molecular Biología Molecular
- La bioquímica es la bioquímica.
Sus antecedentes:
- Los factores de liberación traslacional (RF1 y RF2) terminan la síntesis de proteínas mediante el reconocimiento de codones de parada en el ARNm.
- El mecanismo molecular preciso para detener el reconocimiento de codones y la liberación de polipéptidos sigue siendo incompletamente entendido.
Objetivo del estudio:
- Aclarar la base estructural de la terminación traslacional mediante la determinación de las estructuras cristalinas de los factores de liberación ligados a los ribosomas.
- Proporcionar información a nivel atómico sobre las interacciones que rigen el reconocimiento del codón de parada y la liberación de la cadena polipeptídica naciente.
Principales métodos:
- Se empleó cristalografía de rayos X para determinar las estructuras del ribosoma de Thermus thermophilus complejo con RF1 y RF2.
- Se obtuvieron estructuras de alta resolución (5.9 Å y 6.7 Å) para complejos con RF1 y RF2, respectivamente, unidos a codones de parada cognados.
Principales resultados:
- Las estructuras cristalinas revelan interacciones detalladas entre RF1 / RF2, el ribosoma y el ARNm durante la terminación.
- Se visualizan los elementos clave involucrados en la decodificación y la liberación de péptidos, junto con los cambios conformacionales en ambos factores y en el ribosoma.
- Se observaron distintas interacciones de RF1 y RF2 con la región ribosómica L11, lo que explica los hallazgos bioquímicos anteriores.
Conclusiones:
- El estudio proporciona conocimientos estructurales sin precedentes sobre el mecanismo de terminación de la síntesis de proteínas.
- Los hallazgos aclaran las funciones de los factores de liberación y los componentes ribosómicos en el reconocimiento de los codones de parada y la liberación de cadenas de polipéptidos.
- Este trabajo valida la viabilidad de cristalizar complejos dinámicos ribosoma-factor en estados funcionalmente relevantes.
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