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El mecanismo para la activación de la hidrólisis de GTP en el ribosoma
Rebecca M Voorhees1, T Martin Schmeing1, Ann C Kelley1
1MRC Laboratory of Molecular Biology, Cambridge, UK, CB2 0QH.
Science (New York, N.Y.)
|November 6, 2010
Resumen
Los investigadores revelaron cómo el ribosoma activa la hidrólisis de GTP en la síntesis de proteínas. Una estructura cristalina muestra el factor de alargamiento Tu (EF-Tu) en una conformación activa, crucial para la entrega de aminoacil-tRNAs.
Área de la Ciencia:
- Biología Molecular Biología Molecular
- Biología Estructural Biología estructural.
- La bioquímica es la bioquímica.
Sus antecedentes:
- La síntesis de proteínas se basa en factores de la guanosina trifosfatasa (GTPasa) como el factor de alargamiento Tu (EF-Tu).
- EF-Tu entrega ARN de transferencia de aminoácidos (ARNt) al ribosoma durante la traducción.
- Comprender la activación de la GTPasa por el ribosoma es clave para descifrar la regulación de la síntesis de proteínas.
Objetivo del estudio:
- Para dilucidar el mecanismo por el cual el ribosoma desencadena la hidrólisis de GTP en las GTPasas traslacionales.
- Determinar la base estructural de la activación EF-Tu en el ribosoma.
Principales métodos:
- Se utilizó la cristalografía de rayos X para determinar la estructura.
- La estructura de EF-Tu y aminoacil-tRNA unido al ribosoma se resolvió a 3,2 angstroms utilizando un análogo de GTP.
Principales resultados:
- EF-Tu se observó en su conformación activa.
- Se ordenó el bucle de conmutación I de EF-Tu, con la histidina catalítica posicionada para la hidrólisis de GTP.
- Se identificó una interacción conservada entre la histidina y A2662 del bucle sarcina-ricina del ARN ribosomal 23S como crítica para la activación.
Conclusiones:
- La estructura determinada proporciona información sobre el mecanismo de activación de las GTPasas traslacionales.
- Se sugiere un mecanismo universal para la activación de la GTPasa y la hidrólisis en el ribosoma.
- Este hallazgo avanza en nuestra comprensión del intrincado proceso de síntesis de proteínas.
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